Gundogan's issue for me today was his choice of pass and lack of movement to help his team mates. I think he is good enough, not today though. Tenacity was lacking to.
Example play: Gundogan in centre with ball passes forward to Aguero? with back to goal, 10 yard pass, Liverpool player coming at pace from behind. No call or movement shouting for it right back so he could start again resulting in the ball lost and him not breaking a bollock to get it back. He needs to know the player getting dispossessed is flat footed and he needs to be on it, he wasn't. The pass should never have been played in the first place.
That individual play i would be bold enough to say "Silva would have sorted that" with total conviction.