Goals from in-form striker Ayegbeni Yakubu and prolific defender Joleon Lescott were enough to dispatch a City side which showed no changes from the team which had beaten Manchester United last time out.
"For us to take six points off them this season is really good. To get 50 points at this stage of the season is fantastic and we have to keep building on it.
"But we've not had a penalty this season. We've come not to expect penalty kicks and we've had some that didn't go for us that did matter.
"You'll need to ask (referee's chief) Keith Hackett why. He appoints them, trains them and gets them in condition to referee games."
But City boss Sven-Goran Eriksson played down the importance of two spot-kick appeals, the strongest of which saw Micah Richards handle while on the floor.
He said: "I haven't seen it but it really doesn't matter if it's a penalty or not. A 2-0 is a 2-0."
Eriksson also believes the red card shown to Martin Petrov in the closing stages was a harsh one.
"Some minutes before that (sending off) he did something so that way I can understand it but when it happened I didn't think it was a red card.
"It was not a kick, more like a tap but the referee thought that was right."