#3 Bonucci's nightmare
If Milan's game can be summed up in a single move, it should be that of Bonucci's long pass from the back to Andre Silva towards the end of the game that missed its target by a good 25 yards.
Bonucci had an absolute howler of a game and was one of the main reasons for Arsenal's domination. Other than being responsible for the deflection for the first goal (frankly, there wasn't much he could do about it), he also had a hand in breaking down Milan's offensive displays by misplacing the simplest of passes.
He completed only 41 out of 57 attempted passes; made 0 interceptions and only 3 clearances and did not win any defensive aerials for the team. He had a chance early on to put his side in the lead from a corner, but his header went just wide.
Bonucci would do well to look at Chiellini's performance yesterday against Spurs - it would take an honest repetition of that from him if Milan are to have a chance at the Emirates.