Arsenal breathed new life into their Champions League campaign as Olivier Giroud capitalised on Manuel Neuer's misjudgement and Mesut Ozil added a late second to inflict upon Bayern Munich their first defeat of the season at the Emirates Stadium. Neuer flapped at Santi Cazorla's free-kick and Giroud was free to direct the ball goalwards before Ozil turned home in stoppage time to hand the Gunners the most crucial of victories.
Neuer had earlier denied Theo Walcott's header from point-blank range but the Germany World Cup winner's fortunes would take a remarkable twist with 13 minutes to play. Opposite number Petr Cech, recalled after being dropped for the opening two group games, was meanwhile imperious at the other end, twice keeping out top scorer Robert Lewandowski and Douglas Costa to cap a memorable win for the successive FA Cup winners.
Though Bayern dominated possession for long periods they also lacked impetus and direction as they appeared to cruise towards a point in North London. However, they were stunned by two late Arsenal goals which keeps alive their hopes of reaching the knock-out phase of the competition.
With defeats in their opening two group games, the Premier League side knew it was imperative they avoided another loss in order to give themselves any hope of reaching the knock-out phase. Arsenal had swatted aside Manchester United and Watford since the disastrous 3-2 reverse against Olympiakos and were unchanged - with Cech recalled - in pursuit of a much-needed victory.
Between them and European salvation was a Bayern side who arrived on English shores as the in-form side on the continent. Pep Guardiola's side had won all nine of their Bundesliga fixtures this term and were spearheaded by Lewandowski, who with 24 goals for club and country was outscoring Ballon d'Or favourites Lionel Messi and Cristiano Ronaldo.
The opening five minutes of the game belonged to the travelling Bayern support, who boycotted the start of the game due to the £64 ticket prices imposed upon them for the tie. Applauded by the home fans upon their emergence after kick-off, it provided the backdrop to a tepid start to the game.
Once into their stride, Arsenal wasted little time testing Neuer as Ozil broke through the tackle of Jerome Boating only to see the outstretched arm of his fellow-countryman turn the ball away. Philippe Lahm blocked the follow-up effort as Walcott looked to turn into an empty net
Guardiola was becoming increasingly irate on the touchline at his side's failure to discover any early rhythm. Even when Thiago Alcantara, who escaped in behind Francis Coquelin, did combine with Thomas Muller, Cech was equal to the Spaniard's close range shot; diving to his left to produce a fine reaction save.
Cech was called upon again to keep out Arturo Vidal's strike but despite Bayern's dominance in possession chances were flowing at the other end. Neuer did brilliantly to claw away Walcott's header before Aaron Ramsey's follow-up was driven wide.
Despite being a constant threat on the break, the home side's ambition almost contributed to their downfall when Sanchez's miss-placed pass found Douglas Costa - terroriser of Hector Bellerin in the first half - but Cech tipped his rasping effort over the bar. The Brazilian, who almost joined Chelsea in the summer attempted to catch Cech out again six minutes after the break but his effort flew over.
With Arsenal's momentum from the first half firmly extinguished, Bayern turned the screw but again Cech proved his worth with an acrobatic save to deny Lewandowski. Muller then flashed the ball across goal as the pressure continued to ratchet up on the home goal.
But just as Bayern looked at their most comfortable, their most reliable performer Neuer produced a mistake which could have huge implications for Arsenal in their attempts to stay in the competition. The 29-year-old completely missed Cazorla's free-kick as Muller failed to keep hold of Laurent Koscielny, and Giroud - who had been on the field for just three minutes, bundled the ball into the empty net via an outstretched hand to send shockwaves around Europe.
Koscielny's last ditch tackle kept Lewandowski from pulling trigger when put clean through amid wave after wave of Bayern attacks but as the visitors poured forward they were caught on the break in added-on time. Ozil's cushioned volley from Bellerin's cross appeared to have been initially kept out by Neuer until the assistant referee on the line awarded the goal to settle the game.