The first goal from Barcelona was a thing of beauty, the interception from Iniesta from the backheel, couple of touches leaves Wilshire for dead then plays a perfect through ball for Messi then the dink over the keeper...sublime.
Arsenal were unlucky with the sending off but lucky not to concede a first half penalty, and lucky to have had a Barcelona goal chopped off in the first leg when it should have stood. So they shouldnt IMO feel too hard done by from the officials.