I think he's frustrated because Sunday's line up (with Kolarov at LB) is clearly his preferred team and formation. It wasnt just that Balotelli wasnt playing, it was that he had to rejig the team, with Yaya playing too far forward. He obviously believes that once he gets his best team on the pitch regularly we'll kick on and is frustrated that we cant do that because of Balotelli's suspension.
In the interview he gave on 5 Live he stressed the impact that losing to United 3 times in injury time last season had on the players. Perhaps surprising in that half of yesterdays team didnt play in those matches, but taken with the similar comments made by Micah, its obvious that those games have left some mental scarring which might explain the hesitancy last night.