It was that devastating 5-1 Champions League defeat in Munich that convinced Arsene Wenger it was time to retire. Looking on at yet another humiliating defeat on the biggest stage he realised that his heart was no longer in it. He loved this club and he always would and football would always be his life. But he just couldn't do it anymore.

Despite the difficult draw, Wenger had had faith in his players. Alexis Sanchez had been in great form all season and would surely lead from the front. Laurent Koscielny and Shkodran Mustafi had formed a great defensive partnership. As for the likes of Mesut Ozil, Francis Coquelin and Granit Xhaka who had been struggling through some poor form, Wenger did what he always does and showed confidence in those that he kept under his wing.

However that hope very quickly eroded. Instead Wenger saw his team picked apart piece by piece by a rampant Bayern team, feasting like birds of prey upon his decaying players, leaving Arsenal staring at a first round exit from the knockouts once again. It meant seven consecutive seasons without progressing beyond the round of sixteen and for Mr Wenger that was enough.

He would not announce is retirement publically for a few more months. He did not even tell his players yet. After a mauling in the British press almost equivalent to that received in Munich, they bounced back with an emphatic 4-0 win away to non-league Sutton United in the FA Cup, with Wenger selecting an eleven comprised mostly of fringe squad members. Danny Welbeck scored two goals and assisted another.

Following a draw away to Liverpool (Alexis Sanchez with a second half equaliser after Joel Matip was dispossessed), they then saved some dignity with a 2-1 win against Bayern in the second leg and proceeded to win their next five games, including a 1-0 victory over Manchester City (in which Yaya Toure was sent off with twenty minutes to play), before being held 0-0 by Middlesbrough. Their unbeaten streak ended with defeats away to Tottenham and Manchester United, which again had the press at their throats, but in beating Stoke and Everton in their final two league games they were at least able to salvage fourth place and another season of Champions League football.

Meanwhile in the FA Cup, the win over Sutton earned them a quarterfinal against Burnley, which became a 2-0 win, goals to Walcott and Sanchez. In the semi-final it took an 87th minute leveller to force extra time against holders Manchester United (Giroud with a scrappy finish after Marcos Rojo couldn’t clear a corner) but after thirty non-eventful minutes the Gunners then triumphed on penalties. It looked unlikely when Walcott missed his effort but Paul Pogba struck his attempt over the crossbar and Petr Cech made an impressive save diving to his right to deny Daley Blind for the win.

And so, with Wenger having finally announced his decision publically two weeks prior and having been treated to a wonderful Emirates farewell in the 3-1 win over Everton that ended their league season (there was a guard of honour from both teams, with a plane flying over during the first half carrying a banner reading: Thank You Arsene. The manager himself spoke to the crowd afterwards, albeit briefly, thanking them in turn for all of their support through the years), his final game came at Wembley Stadium with the opportunity to deny Chelsea (who had beaten Tottenham 1-0 in their semi) from doing the domestic double.

Unfortunately the dream finish was spoiled by a Diego Costa goal in the 35th minute, reacting quicker than the defence as Cech’s diving save from Eden Hazard’s shot bounced back to the left of the goal. Chelsea won 1-0 and Antonio Conte paid tribute to Wenger’s wonderful success and longevity in his post-match press conference.

Of course the focus now shifted from saying farewell to Mr Wenger to finding a replacement for him. There were several candidates, albeit none that appeared to be perfect fits. Thomas Tuchel of Dortmund took himself out of the running very early by reaffirming his commitment to his current job. Diego Simeone was another linked in the papers who denied any interest in leaving Atletico. La Gazzetta dello Sport printed a story that Massimo Allegri of Juventus was in conversations with Arsenal representatives, though despite being linked to this job for several months Eddie Howe’s poor form with Bournemouth, only escaping relegation in the second to last game as they beat Stoke 3-2, seemed to have ended his chances – despite what appeared to be a strong campaign on his behalf from the Daily Mail.

Both Laurent Blanc and Joachim Low were given interviews, however neither side was able to bridge the financial differences. Brendan Rodgers offhandedly talked his candidacy up after a Scottish journalist asked him about his success with Celtic, though there was never any evidence that he was being serious. As for Harry Redknapp’s comments on twitter, they were almost certainly meant tongue-in-cheek.

Finally it came down to a shortlist of three managers: Patrick Vieira, Roberto Mancini and Marco Silva. It was understood that Luis Enrique would have gotten the job had he parted ways with Barcelona but the club and manager decided to pursue their combination despite Barca only finishing second in La Liga. Enrique would remain in that job for another ten months before being fired.

Of the trio, Vieira was the fan’s choice and there was a particularly impassioned video on Arsenal Fan TV about “getting back to the glory years” and “respecting our history” although Vieira’s inexperience appeared to count against him - as did his current employment with City Football Group. Marco Silva also lacked experience even if the way he came so close to keeping an embattled Hull City squad from relegation won many fans. Plus there were those that considered Sam Allardyce’s tactics and conduct in that game which ultimately doomed Hull, the 1-0 defeat to Crystal Palace in the second to last game, to be less than becoming and Silva’s dignified reaction was widely applauded. As for Mancini, he had famously managed against Wenger for several years with Manchester City and despite an ignominious exit from Inter Milan the previous August, his title-winning pedigree and Premier League experience made him the frontrunner and sure enough it was he who, on July 3, was unveiled as the new Arsenal manager – only their second manager since 1997.

Mancini was defiant at his first press conference, speaking fervently about bringing trophies to the club and signing big players. He very notably made no reference to his predecessor outside of his initial statement acknowledging all of Wenger’s service to Arsenal. Mancini vowed to get straight to work and, true to his promise, his first game in charge was two weeks later in Australia against Sydney FC. They drew 3-3 but Mancini used it more, as he would two days later against Western Sydney (a 4-1 win), as a chance to get a look at as many of his players as possible.

Arsenal went on to win the rest of their pre-season games, all played in England and Italy. There was growing hope that the team could sustain a title challenge under their new manager just so long as they could make a couple of crucial transfers. Well, Mancini wasted no time in trying to exploit his Man City connections to sign Sergio Aguero, with the Argentinian having handed in a transfer request the month prior. Aguero expressed an interest in teaming up with Mancini again yet in the end decided on a move to Real Madrid instead. Looking to take advantage of that Arsenal submitted a bid for Alvaro Morata, however Karim Benzema’s move to Paris Saint Germain meant that Madrid were no longer interested in selling. A £45m bid for PSG’s Edinson Cavani was also rejected.

Dramas were already growing within the squad as well. Both Alexis Sanchez and Mesut Ozil had earlier said that their contract extensions depended on Wenger also staying and now each was reportedly quite unsettled. Mancini held personal meetings with each of them and succeeded in convincing Sanchez that they could achieve all of his goals there at Arsenal and he agreed to a new contract, though Ozil was ready to move on and nothing could convince him otherwise. After an unconvincing end to the previous season, the fans were also accepting, if reluctantly so, of Ozil’s position. Interest arose from Manchester City, Dortmund, PSG and several clubs in Italy. Eventually he agreed a four year contract with AC Milan for a £20m fee. Theo Walcott also left the club, returning to Southampton for £18m, citing his desire for new challenges.

But the Gunners were not without a few strong moves of their own. With Leicester City responding to their relegation with a hastily arranged garage sale, Arsenal were able to secure the signatures of both Kasper Schmeichel and Riyad Mahrez for a combined £28m, Schmeichel expected to compete for the starting goalkeeper role as Petr Cech’s form began to decline at age 35. No striker was forthcoming but they did re-sign Bacary Sagna from City for some fullback depth and in their £30m marquee deal they were able to agree a deal for Ivan Rakitic from Barcelona.

Come the start of the season, Mancini was able to call upon a fully fit squad and his first two games were very impressive. A 2-0 win over Crystal Palace saw Giroud find the net before Sanchez set up Mahrez on debut. That was followed by a 4-1 demolition of promoted Brighton, Sanchez scoring twice and Lucas Perez adding one off the bench before Granit Xhaka’s late thunderbolt ended it. However a 1-1 draw with West Ham stifled the atmosphere around the club somewhat, especially the way they conceded that goal to Andy Carroll.

Having eased into the Champions League group stages with a 3-0 aggregate win over AIK, Mancini’s team were drawn with Atletico, Dynamo Kyiv and FC Copenhagen. Giroud scored the winner as they beat Copenhagen 1-0 away to begin that competition. Three days later they suffered their first defeat of the season, Schmeichel fumbling a shot from Nacer Chadli which allowed Salomon Rondon to score the only goal of the game for West Brom. Sanchez had earlier missed a penalty (awarded for handball against Jonny Evans).

Despite calls from the fans for Santi Cazorla and Mohamed Elneny to return to the starting team, Mancini went with Coquelin and the reintegrated Jack Wilshere in midfield for the game against Manchester City, a big game for Mancini versus his old team. The selections soon backfired. Coquelin conceded a free kick on the edge of the box fouling Gabriel Jesus and Kevin De Bruyne beautifully scored from the set piece. Five minutes later Arturo Vidal played in a lovely ball to Jesus, who was able to beat Koscielny for pace before squaring it to Leroy Sane for 2-0. Although Arsenal didn’t play too poorly after that, they couldn’t find the net and Kelechi Iheanacho finished them off with quarter of an hour left. 3-0 to Manchester City and with seven points from five games, Arsenal were back in mid-table.

Losing 1-0 to Atletico Madrid didn’t help either. Mancini continued to exude a quiet confidence that things would turn around but they took a dramatic turn when one of Alexis Sanchez’s beloved dogs was struck by a car and, emotionally distressed, he requested some time off to nurse it back to health. Being in no fit state to play, that leave was granted. Without him there was an opportunity for Mahrez to string some consecutive starts together but an ankle injury put an end to that for three weeks – during which they’d face both Dynamo and Liverpool, as well as Burnley.

Rakitic scored his first goal for the club against Dynamo in a game which ended in a 1-1 draw. They were then held scoreless by Burnley (a game best remember for the fight between Granit Xhaka and Joey Barton that earned each of them five match suspensions) before Liverpool came to the Emirates and, continuing on their own hot form that season, came away with a 2-1 win, the winner scored by Pierre-Emerick Aubameyang.

Now the pressure was really on Mancini and he began to take a markedly cynical attitude towards the press. Rumours of a personal fallout between himself and Olivier Giroud were never confirmed, however when Lucas Perez scored twice to beat Everton there was an incident where Giroud refused to warm up on the bench which was caught by the TV cameras. Possible transfer destinations for the Frenchman dominated the tabloids the next day.

It was around this time in late-October that Arsene Wenger made his first public appearance since retirement as he sat down for an extended BBC interview with Gary Lineker to commemorate his 68th birthday. In it he distanced himself from the current team’s issues, preferring to chat about the many great players he worked with and the football that they played in his time. Compared to the free-flowing style of Wenger, Mancini’s team had begun to draw a reputation for being overly conservative. Having long demanded a more pragmatic approach, fans were now speaking fondly of the style of years past.

The Gunners were entering a potentially crucial stretch of their season and those players that Wenger spoke of so fondly were suddenly speaking in opposite tones about Mancini. Thierry Henry was particularly scathing in his punditry for Sky Sports. Asked by Gary Neville if he’d consider taking the job as manager if Mancini was fired, he didn’t rule it out.

In the return game against Dynamo, Arsenal thoroughly controlled the game and had 15 shots on target but somehow couldn’t score. Both Sanchez and Mahrez were back in the team by now and they were particularly to blame for the profligacy in that 0-0 draw, which left the Gunners needing a result against Atletico to rekindle their chances of making the UCL knockouts. With a game against Manchester United coming several days later, Jose Mourinho made several pointed remarks about what a great manager Arsene Wenger, his old rival, was and how much he missed him. Mourinho also added how difficult it can be to replace a legendary manager, alluding to his own steadying of the ship at Manchester United but also, as several football writers deducted, subtly referring to Mancini’s own difficulties.

Mancini responded with fury in his press conference. Words like “disrespect” and “unacceptable” were used and before kick-off he refused to shake Mourinho’s hand. The game itself was a combative one in which there were more fouls than shots and neither team looked like they were willing to risk a more proactive approach. As it turned out, Manchester United didn’t need to because an hour into the game Paul Pogba dispossessed Aaron Ramsey and lobbed the ball long to Henrikh Mkhitaryan, who dribbled around Monreal and was fouled from behind. Penalty. Up stepped Zlatan Ibrahimovic who converted for the only goal of the game. Mancini was furious at the decision, despite replays suggesting that it was the right call, and was sent to the stand for putting a hand on the third official. The Old Trafford crowd ended the game chanting: “You’re getting sacked in the morning!” but there was no reason to sack him. He handed in his resignation later that night.

In a shocking move, Arsenal appointed Henry as their caretaker boss while the search for Mancini’s replacement began. Initially he was able to coax some more belief out of the team as they went to Madrid and came away with a fighting draw against Atletico, although Dynamo’s 1-0 win over the Spanish side in the final gameweek meant that even with their 3-1 win over Copenhagen (goals to Welbeck, Rakitic and Giroud – the latter now reintegrated in the squad) Arsenal could only finish third and were eliminated from the Champions League at the group stage for the first time since 1999-2000.

The club were lingering in ninth when Henry took the reins. A couple of wins over Newcastle and Middlesbrough lifted them up to seventh though already they were 15 points behind leaders Manchester City and eight points behind fourth placed Tottenham. There was a fan protest held to convince the owners to hire Thierry Henry on a full time basis, with roughly 400 people picketing outside the Emirates Stadium, but Henry said he had no intention of staying any longer. Still, without any convincing candidates at this stage he was forced to stay on until after Christmas. Boxing Day was celebrated with a 1-1 draw against Chelsea, a result that came as a reward for one of their better performances of the season, even if the long term injury to Aaron Ramsey was a setback. In the New Year it was confirmed that Wenger’s former assistant Steve Bould would take charge of the team for the rest of the season, with a long-term boss to be appointed after its conclusion.

Arsenal’s League Cup run ended in the semi-finals as Chelsea came through with a 3-2 aggregate win, taking the Stamford Bridge leg 3-1 to overturn a 1-0 Gunners win at the Emirates. Bould got consecutive 1-0 wins over West Brom and, crucially, Spurs – Mahrez with a gorgeous curling shot from his left foot for the difference in the latter. That kept alive their chances of making the top four, chances which took another hit when Stoke kept them to a draw. A second string team was knocked out of the FA Cup by Rafa Benitez’s Newcastle the next week, granted fans were happy to sacrifice that competition if they could get back into the top four. With 15 games to play they were still seven points behind Spurs and injuries to Sanchez (hamstring) and Xhaka (knee) meant they were also undermanned in the chase.

One player who really played well under Bould was Elneny. As the least fancy of their midfield options, he hadn’t been given much of a run by Mancini but with injuries thrusting him into the spotlight, his composed passing game became influential. Similarly Danny Welbeck, after a couple of minor injuries in the first half of the season, began to force his way into the top strength XI. Olivier Giroud scored a late winner to beat Burnley and Welbeck was able to outjump Kyle Bartley at the far post to head in the decider against Leeds.

The Europa League campaign therefore meant they had an alternative route into the Champions League which they couldn’t afford to dismiss. Drawing FC Basel in the round of 32, it was an emotional day for Xhaka and Elneny who both used to play for the club. Fittingly, Xhaka slid in the first goal from the edge of the area and Arsenal comfortably won the tie 4-1 on aggregate. In the next round they drew Bayer Leverkusen and had a much tougher time, holding onto an away goals lead for the final twenty minutes after Javier Hernandez’s goal made it 3-3 overall. They survived, and drew Liverpool in the quarters.

With eight games remaining in the league, Arsenal were sixth and four points behind Spurs, with Chelsea in between them a point behind Tottenham (they’d been having trouble finding goals since Diego Costa left for Chelsea). Along with those two games against Liverpool they also had to play Manchester City, Man United and Spurs again. The home leg against Liverpool ended 0-0 and, without any away goals conceded, the experts considered it a tie very much in the balance. They beat Bournemouth 4-0 in the next game and coupled that with a 2-1 victory against Watford.

The European dream ended abruptly the next week. Liverpool put out the best possible team they could and their blend of pace and pressing was too much to handle for the tired Gunners. Coutinho was brilliant scoring twice and assisting another while Aubemeyang and Mane looked untouchable. Milner scored from the spot and even after Perez pulled one back, hope only lasted a few minutes before Jordan Henderson’s pass in over the defence found Aubemeyang who crossed to Adam Lallana to make it 4-1. It was a superb performance by Liverpool, who would go on to win the tournament (as well as finishing second in England). For Arsenal it was a blow they couldn’t really afford. Things improved against Man United for a 2-2 draw but they really should have won from 2-0 up and Marcus Rashford’s equaliser might not have been enough to keep United’s title challenge alive but it meant they held onto third place for another week, a position they’d maintain until the end.

Swansea were no match for a fit-again Alexis Sanchez (who was now strongly understood to be leaving the club in the summer) but Spurs managed to beat West Ham in the same weekend as Harry Kane scored in injury time from the spot. It was controversial, to say the least. The Gunners were given a boost when Man City came out on top of Chelsea the next week and they took advantage of that by beating Brighton 2-1 – although only just, as Cech saved a penalty with ten minutes to play that would have tied things. Having started the season on the bench, Cech found his way back in as starting keeper under Henry and maintained that position for most of the season.

But the good luck ended away to Manchester City when a Gabriel Jesus masterclass all but secured the title for the Sky Blues and left Arsenal lingering in sixth again, now five points behind Spurs and anything but a win the next week would mean they finished outside the top four for the first time since 1995-96. Well, they drew 1-1 at Wembley against Tottenham and that was that, also ending the long tradition of St Totteringham’s day - Harry Kane’s 17th minute goal cancelling out Danny Welbeck’s 5th minute opener.

On the final weekend of the season, Arsenal looked completely disinterested as they lost 1-0 to Middlesbrough, Boro ensuring Premier League survival with the win while Arsenal slipped back to seventh behind Wayne Rooney’s Everton (Rooney taking over as player-manager late in the season with Ronald Koeman leaving to take charge of Barcelona, which he had already referred to as his “dream job” before he was even offered it).

With Luis Enrique now available, there were short odds on him getting the Arsenal job for the 2018-19 season but thanks to that final day capitulation he would be taking over a team without European football. Arsene Wenger was in the crowd for that Boro defeat, sitting alongside a few family and friends. Several times the cameras cut to his face in the stands as the game stuttered towards its conclusion but if Wenger was feeling any emotions one way or the other then his stonewall expression sure wasn’t showing it.