A supposedly inferior Dinamo Zagreb had done their homework, and let Arsenal have the ball for long periods uninterrupted but still created better chances and looked by far the more threatening side. This Arsenal team has enough technical quality that they should be able to break down the likes of Zagreb, but more importantly they should be well aware of the risks of playing so high up the pitch. Mikel Arteta – who is plainly not, never has been and never will be a defensive midfielder – was stationed as the deepest player in the middle of the park yet, once again, he failed to provide sufficient cover to his defence. Francis Coquelin was understandably rested but Wenger cannot rely on Arteta as his back up.
http://www.telegraph.co.uk/sport/football/teams/arsenal/11869098/Dinamo-Zagreb-vs-Arsenal-five-things-we-learned.html