Here is a run-down of the key battles...
Mario Mandzukic vs Per Mertesacker
The Croatian scored in bizarre fashion at the Emirates, and will be looking to find the net again to finish off Arsenal. Mandzukic has become an important man for Bayern, not only scoring plenty of goals this season but also holding up the ball for their talented midfield to run onto. If Mertesacker allows Mandzukic space to get on the end of Bayern's crosses, he will put this tie to bed however Arsenal do going forward.
David Alaba vs Theo Walcott
Having toiled without success as a central striker in the first leg, Walcott will likely return to the right flank on Wednesday, where he will face off with David Alaba. Alaba has been superb for Bayern this year, and his breaks forward are an important part of their attacking threat. Walcott will need to track Alaba back, whilst also exploiting any chance he gets to break at Bayern's centre backs.
Javi Martinez vs Santi Cazorla
Both of Martinez and Cazorla have made a big impact in their first seasons at their new clubs, and Cazorla in particular will be vital for Arsenal in this match. The Spaniard will have to carry the threat from midfield without the support of Jack Wilshere, and how much possession he is able to get in the final third will be a major factor in Arsenal's attacking success. Martinez will be looking to ensure Cazorla has a minimal impact on the game, and the 40 million Euro signing has been very effective against most players he has come up against this season.
Arjen Robben vs Keiran Gibbs
Arsenal will be desperately hoping that Gibbs makes the match, with Bayern likely to play Arjen Robben on the right and move Thomas Muller across to cover for Franck Ribery. Robben showed in his substitute appearance how threatening he can be cutting in from the right, and Gibbs will have to track him carefully. Gibbs will be important to Arsenal's attacking play as well, but must not get caught upfield and leave Robben with room on the break, as the Dutch player will likely punish him severely.
Dante vs Olivier Giroud
Having missed out on a starting place in the first leg Giroud will likely feature on Wednesday night as Arsenal attempt to overturn the deficit. Dante and Bayern looked comfortable against Walcott by himself at the Emirates, but it will be interesting to see if Giroud's physical presence can cause them more problems, especially if the Frenchman can hold the ball up for Walcott and Cazorla.
image: © Lorenzo Blangiardi