Bayern Munich 5-1 Arsenal: Muller, Robben, Thiago and Lewandowski fire in goals as Gunners crumble in Germany
Bayern Munich have annihilated Arsenal in the first leg of their Champions League last-16 tie at the Allianz Arena in Germany, beating the London club 5-1.
The Gunners have fallen at this stage in the last six years and now need to produce a miracle performance at the Emirates Stadium to overturn the heavy deficit and progress to the quarter-finals.
Arjen Robben had put Bayern ahead with a superb goal but Alexis Sanchez drew the visitors level with a well-taken finish after seeing a weak penalty saved.
Arsene Wenger, who side have lost five first legs in those six defeats at this hurdle, then saw his team rattle their hosts only to be blown away courtesy of a Robert Lewandowski header and a Thiago brace in 10 second-half minutes before a late strike from substitute Thomas Muller added the gloss.
Wenger had opted to field David Ospina rather than Petr Cech in goal, while Alex Oxlade-Chamberlain and Alex Iwobi were tasked with dropping back into a four-man midfield when Arsenal were defending.
Wenger's goalkeeping decision made no impact on the opening goal as Robben moved inside unchallenged before bending a superb effort past the desperate dive of Ospina.
Bayern dominated possession for much of the opening half as Arsenal remained boxed in defensively, although Sanchez won a free-kick on the edge of the penalty area after bursting forward at pace and being fouled by Mats Hummels.
Ozil hit a tame free-kick, which Manuel Neuer made hard work of, but the Germany goalkeeper was equal to Sanchez's penalty after referee Milorad Mazic pointed to the spot having adjudged that Lewandowski had fouled Laurent Koscielny.
Although he missed the resulting spot-kick, Sanchez recovered and after fluffing his lines again managed to tuck away the equaliser.
The Gunners were growing in confidence and, after Ozil and Sanchez combined, the latter slipped in Oxlade-Chamberlain whose cross dropped to Granit Xhaka, but his firm shot was straight at Neuer.
Lewandowski then passed up a glorious chance to make amends for conceding the penalty as the striker could only head a David Alaba cross over from in front of goal.
While the hosts remained a threat throughout the first half, Arsenal were also more involved as an attacking force and Ozil bought a smart stop out of Neuer on the stroke of half-time.
The game and the tie arguably hinged on an incident on 49 minutes when Koscielny over-stretched to make a clearance and was forced off, with Gabriel on in his place.
Less than 15 minutes later and Arsenal were three goals behind as Lewandowski nodded home Philipp Lahm's cross before flicking a pass into the path of Thiago, who slotted home coolly.
Arsenal were rocked and could have conceded again as Ospina rushed off his line to harry Lewandowski, who turned a shot against the bar before Robben's rebound was deflected behind.
The Colombian goalkeeper atoned for his error by making a superb point-blank save from the busy forward, but he was soon beaten again as Thiago's strike came off Xhaka and into the net.
Still chances kept coming Bayern's way, Ospina getting down well to push Vidal's low drive wide on the post before tipping Douglas Costa's strike behind.
Muller came off the bench to a heroes welcome as Lewandowski made way, and despite having only four minutes to make an impact he did just that as he converted the fifth as Bayern beat Arsenal 5-1 for the second meeting in succession.
Arsene Wenger will risk the ire of Arsenal supporters after deciding to play David Ospina rather than Petr Cech in the first leg of their Champions League round-of-16 clash with Bayern Munich on Wednesday.
Cech, the only previous winner of the competition in the Arsenal ranks, will be warming the bench at the Allianz Arena - the venue for his Champions League success with Chelsea - as Wenger sticks by Colombia international Ospina.
The 28-year-old played all six of the Gunners' group matches as they finished unbeaten to advance in first place.
Wenger had the same rotation policy last season but drafted Cech back in for this stage as his side were knocked out by Barcelona.
In fact, Arsenal have been eliminated at the round of 16 for the past six seasons but, despite some question marks over Ospina after a couple of poor displays last year, Wenger has backed the Gunners stopper in a big way.
"I have nothing to hide there, it will be Ospina because of the quality of his performances," the Arsenal boss replied when asked about which goalkeeper would start the game.
"We are in the last 16 and finished top of the group, if you analyse his performances in every single game we are where we are because of his great performances."
Wenger also suggested Mesut Ozil would start on Wednesday after he said the German World Cup winner was lacking confidence in recent games.
Ozil has not scored since December 10 and has been a peripheral figure for many of Arsenal's last fixtures, including the two recent defeats to Watford and Chelsea.
"I will pick the team on Wednesday morning," he said when asked if Ozil would play.
"I have no doubt that we play in Germany and Ozil is highly focused to have a good performance.
"Ozil has been playing for us for many years now and he knows perfectly our team and he knows how we want to play in every match. So it is an important match."
The move is made all the more bold by the fact Arsenal's form domestically means they are all-but out of the Premier League title race after two defeats in their last three games.
Because of that run, Wenger has again seen a minority of fans calling for him to leave, with his current deal expiring at the end of the season.
But Bayern boss Carlo Ancelotti, who came up against Wenger while manager of Chelsea, believes the Frenchman should now be immune to any criticism.
"Wenger has the experience to know that in our job it is normal to be criticised," said the Italian.
"For this reason he has no problems. He built a strong identity in this club, he built a really good style of football. I have a lot of respect for the job he has done at Arsenal."