Arsenal were reduced to 10 men in the first half when Wojciech Szczesny was sent off for a foul on Arjen Robben and the holders made their numerical advantage count after the break with goals from Toni Kroos and Thomas Muller.
|13/2||Arsenal are 13/2 with PaddyPower to win the second leg in Munich|
"I think we started really well," the 29-year-old told Sky Sports. "[We] deserved one goal at least. Afterwards we dropped more with the red card and it was even more difficult.
"We are looking forward to Munich. Why can’t we repeat that from last year?"
Mertesacker did hint, though, that tiredness may have caught up with the Gunners as they failed to stop Pep Guardiola's side from leaving north London with a 2-0 win.
"We played four games in the last two weeks [and] Bayern are a fantastic team [who] keep possession. We tried everything and would’ve deserved that first goal.
"We have to take that defeat [but] overall we are stronger than last year. There are a lot of ifs and buts but we must take the result.
"It’s a bit of blow for us, we must remind ourselves of last year. They underestimated us and we showed great spirit.
"We have to switch on Saturday in the Premier League and get three points and after that we have a break that we need desperately."
On the penalty that Robben won in the first half, the German said: "I don’t have a view of the red. There was contact I don’t know if it’s a red. The ball [is] far away from the goal but he touched him so for sure it’s a penalty."