Arsenal's hopes of reaching the Champions League knock-out stages are hanging in the balance after they were thumped 5-1 by Bayern Munich.
Arsene Wenger's men were completely outclassed at the Allianz Arena on Wednesday night as the rampant hosts inflicted the Gunners' joint-heaviest ever Champions League defeat.
From Thiago Alcantara's brilliant performance to Arsenal's dismal defending, here are some of the top talking points from the game...
Brilliant Bayern sparkle
Two weeks on from Arsenal's unlikely 2-0 win at the Emirates Stadium, Bayern brutally claimed their revenge. The hosts ran rings around their prey in an utterly one-sided first half, and the heavy defeat looked inevitable after Robert Lewandowski's opening goal. The scoreline probably shouldn't have come as a surprise. Bayern had averaged 5.25 goals per game in their previous four Champions League home games, and they have been equally prolific in the Bundesliga.
Arsenal pulled a goal back through Olivier Giroud in the second half, but Bayern re-established their four-goal advantage when Thomas Muller struck his second in the closing stages. In truth, it could have been far worse for Arsenal. Bayern had 13 shots on target to Arsenal's two, and the hosts also enjoyed 67 per cent of the possession. As poor as the Gunners were, it is difficult to imagine any side stopping Bayern in this kind of form.
Injuries cost Arsenal
Arsenal's task was made even harder when Laurent Koscielny became their 10th first-team player to be ruled out by injury in the build-up to kick-off. The French centre-back was only fit enough for the bench, and his absence together with that of Hector Bellerin robbed Arsenal of the two paciest members of their back four. Their replacements, Gabriel Paulista and Mathieu Debuchy, struggled badly.
Gabriel's poor positioning played Lewandowski onside for Bayern's first goal, and Debuchy failed to connect with a clearance in the moments before Muller's second. Soccer Special pundit Charlie Nicholas was particularly unimpressed by the opener. "Lewandowski just ghosts into the position, it's not even a sprint," he said. "Gabriel went to sleep and Petr Cech's got no chance. Mertesacker was slow, Gabriel was slow."
Thiago masterclass
Plenty of Bayern players could make a claim for the man-of-the-match award, but Thiago Alcantara was surely the most deserving. The 24-year-old ran the show in central midfield, dictating the tempo of the game and picking holes in Arsenal's defence throughout. He had a remarkable 147 touches of the ball - twice as many as any Arsenal player - and he completed 113 of the 125 passes he attempted.
His performance included stepovers and no-look passes galore, and he also fashioned more scoring chances (four) than any other player, including the assist for Lewandowski's opener. He was equally impressive in a defensive sense, making more tackles and interceptions combined (12) than anyone else on the pitch. Guardiola could hardly have asked for more, and Arsenal simply didn't have an answer.
Olympiakos pile on the misery
Arsenal's evening went from bad to worse when news filtered through of Olympiakos' stoppage-time winner against Dinamo Zagreb in the other fixture in Group F. The Croats seemed to be heading to victory in Greece as they went 1-0 up and Olympiakos missed a penalty, but the hosts equalised midway through the second half before clinching their dramatic winner.
A victory for Dinamo Zagreb would have significantly boosted Arsenal's hopes of advancing to the knock-out stages, but they are now six points behind Olympiakos in third place. The Gunners must claim maximum points in their final two games and hope Olympiakos don't spring a surprise at the Allianz Arena.
Can Arsenal recover for the derby?
Arsenal must now put this defeat out of their system before the north London derby against in-form Tottenham on Super Sunday. "It's a much more important game," said Charlie Nicholas on Soccer Special. "This is about survival in the Champions League at the moment, if it doesn't happen, it doesn't happen. But they won't be forcing themselves to get in the Europa League.
"Arsenal's seriousness this season is in the Premier League," he continued. "The defeat is damaging, of course it's damaging, but I expected Arsenal to get beat tonight. It can happen to you." Arsenal responded to their 3-0 Capital One Cup defeat to Sheffield Wednesday by beating Swansea by the same scoreline in the Premier League - it is crucial they produce a similar response on Sunday.
Watch Arsenal v Tottenham live on Sky Sports 1 HD from 3.30pm on Sunday