Arsenal must deal Bayern Munich its worst home loss in Champions League history to reach the quarterfinals.
Bayern won 3-1 in London and is the highest-scoring team in this season's Champions League (18 goals), while Arsenal is one of the two teams with the worst defensive record (11 conceded). Bayern has only lost nine times in 82 Champions League home matches, and never by more than 2-0.
Arsenal forward Gervinho believes "a miracle'' is still possible and manager Arsene Wenger said the return leg Wednesday was not "mission impossible.''
Bayern will be missing Franck Ribery and Bastian Schweinsteiger but Jupp Heynckes' team is in such form that the coach gave his top players a day off after Saturday's harder than expected 3-2 Bundesliga win over Fortuna Duesseldorf.
"Arsenal is not just any club,'' Heynckes said. "I know that we need 100 percent commitment in such a game.''
Bayern captain Philipp Lahm suggested his teammates should take the game as if the result of the first leg was 0-0.
"But we know we are in a good form,'' Lahm said. "It's going to be tough for Arsenal, they have to defend well and still score three goals.''
Arsenal will be without key midfielder Jack Wilshere, who was ruled out for three weeks Tuesday with an ankle injury. Striker Lukas Podolski, whose career included an unhappy stint with Bayern, is also out with an ankle injury, while goalkeeper Wojciech Szczesny is rested. His place will be taken by Lukasz Fabianski.
Ribery is out with an ankle injury, while Schweinsteiger and defender Jerome Boateng are suspended. Defender Holger Badstuber is out for the season with a knee injury.
Heynckes said Ribery's injury was not serious but the coach could not give a timeframe for his return.
Ribery's place is likely to be taken by Arjen Robben, who missed the game against Duesseldorf with a light calf injury but is ready to play Wednesday.
Midfielder Thomas Mueller said Bayern has to be focused and cautious "because this is a knockout game.''
"But we are not going to sit back and crowd the defense,'' Mueller said. "They have nothing to lose, they can attack all the way. We have to be careful.''
Bayern is dominating the season at home - it is 20 points ahead in the Bundesliga, it has reached the semifinals of the German Cup and is on the verge of advancing to the quarterfinals in the Champions League. Bayern is a four-time winner and was runner-up in two of the last three seasons.
If Arsenal is eliminated, England won't have a team in the last eight for the first time since the 1995-96 season.
"We just need to keep positive and give everything we have. We all know anything can happen in football,'' Gervinho said. "Personally, I still believe we can make it. I know it will be difficult, but I still believe in us.''
Bayern Munich has won all three home games in the competition this season but Wenger believes his team can still go through.
"It is not mission impossible,'' the Frenchman said. "It can be done, but first of all you need 100 percent commitment, attitude and things to go your way. But usually football goes your way when you have the right attitude.''