In my opinion, and I hope its quite clear, Dzeko's reaction was because he was way below his own standards, not only tonight but in the previous 3 games and perhaps the last 10 months.
A combination of Balotelli propelling us to victory against Everton and having a poor game against a team from his former league will have compounded this.
I feel happy to have such a determined player in out squad. Yet I shall say again, Dzeko does not have the turn of pace/balance to be a world class centre forward.
Name me a top team which plays with a striker as immobile as Dzeko.
It frustrates me when people post - 'oh but Dzeko and Aguero misplaced 97.5% the same passes tonight, and neither had many shots' : Aguero is a constant threat, Dzeko is not.
