Munich (Germany) (AFP) - Arsene Wenger slammed Arsenal's "extremely poor" defensive display at Bayern Munich as their record 5-1 defeat left them with just a slender chance of progressing in the Champions League. Thomas Mueller scored twice on Wednesday while Robert Lewandowski, David Alaba and Arjen Robben were also on target as Pep Guardiola's Bayern emphatically avenged their 2-0 defeat at the Emirates Stadium a fortnight ago. This was Arsenal's joint heaviest away defeat in Europe, equalling the 4-0 drubbing at AC Milan in the last 16 in February 2012. France striker Olivier Giroud scored Arsenal's consolation goal with 20 minutes left, but with two games to go, Arsenal have only a mathematical chance of reaching the knock-out phase after Dinamo Zagreb's 2-1 defeat at Olympiakos. The Gunners have three points along with Dinamo, while Olympiakos and Bayern both have nine with the Germans top of Group F on goal difference. It means Arsenal must win their final two matches at home to Zagreb and away to Olympiakos, plus hope Bayern beat the Greek side at the Allianz Arena in a fortnight to progress. "You have to give credit to Bayern for their quality, but we made life easy for them and we were extremely poor defensively. We weren't at the races," admitted Wenger. "We did well going forward, we created chances, but with a defensive display like that, you are going nowhere." - 'nothing positive' - Wenger balked when asked if that was the worst defensive display he has witnessed since taking over as Arsenal coach in 1996. "My memory isn't good enough to tell you if that is the worse defensive performance in 19 years and it won't stay in my memory as anything positive," said the 66-year-old. "We still have a chance to qualify. Olympiakos have to win here and we have to beat Zagreb at home, then beat Olympiakos away. "It's a small chance but it is a real one and we have to give our all to have a chance of qualifying. "I think we have to realise with that kind of performance like today, our chances are very minimal." The Gunners have to pick themselves up now for Sunday's north London derby at home to Tottenham Hotspur with Arsenal second in the Premier League table. "We have to put focus on the Premier League and put in a better performance on Sunday," added Wenger. "We can't be too negative, but at the same time we have to face reality. "That's top level sport. We have to be strong enough to accept our performance was not good enough and accept that we have not become a bad team overnight." Having had a lengthy injury list in Munich, Wenger proved he had not lost his sense of humour by quipping they had picked up no new knocks, "apart from in a few heads". Bayern can do Arsenal a huge favour by beating Olympiakos in two weeks' time and Guardiola said his side will be going all out to defeat the Greeks as they target finishing first. "Arsenal can be sure that we will be going out to beat Olympiakos to do our best to be first in the group," said Guardiola. "They have the same points as us so you can be sure we are going to try." "That was a big step towards reaching the knock-out phase and was one of the best performances in my time here. "We were very brave in front of our own fans, but we still have some improvements to make. "People wanted us to show a reaction from the defeat in London and that is what we did." Join the conversation about this story »