This was never going to be an easy game to win, because Bayern, but here we are, down 2-0 after the first leg and not feeling great about it, because it could have been so different.
Arsenal had a golden chance early when Özil was brought down by Boateng and the ref pointed at the spot. The resulting penalty, uh, didn't go well. Arsenal's cause wasn't helped when Szcz was sent off in the 37th minute for a foul on Arjen Robben. Fortunately, Bayern missed the penalty, which was sort of justified given the truly "it could go either way" nature of the foul.
They saw out the half OK, but the second half was a different story - Bayern came out guns blazing, and Arsenal looked, even despite the rules that limit there to two teams on the pitch in a single match, like the third or fourth best team on the pitch. The inevitable happened in the 54th minute, when Toni Kroos did this. The rest of the half went no better, and in the 88th minute, Arsenal took another kick to the nuts when Thomas Muller scored.
Still. I'm choosing to look at the positives. 2-0 down going into the second leg? Not great, sure, but also not impossible. Arsenal won in Munich last year, after all, and considering that everyone expected this game to end 528-3, I gotta say I'm not despondent at a 2-0 even given how Arsenal were outplayed in the second half. Defending, as usual, kept Arsenal in the game.
Go forth and vent.