Following City's remarkable 6-1 derby triumph at Manchester United and their 5-2 Carling Cup win at Wolves on Wednesday, many were expecting today to be a comfortable assignment for the free-scoring Blues at the Etihad Stadium.

However, it took until seven minutes into the second half for City to break the deadlock when Edin Dzeko converted the loose ball after Sergio Aguero had pounced on some hesitant play by goalkeeper Wayne Hennessey, who then parried David Silva's shot to allow Aleksandar Kolarov to make it 2-0 in the 67th minute.

City were reduced to 10 men with 15 minutes remaining as Vincent Kompany was sent off for bringing down Kevin Doyle.

Stephen Hunt converted the resulting penalty and with second-placed United having beaten Everton earlier in the day to narrow the gap at the summit, things were looking tense as the game neared its conclusion.

However, substitute Adam Johnson slotted home City's third in stoppage time and Mancini said: "It is impossible to always score four or five goals.

"I don't know how many chances we had in the first half today, but their goalkeeper saved everything. But in the second half I think we played very well and it was important to beat Wolves today.

"After the Man United win I don't want us to think that every game will be easy. This does not exist in football, in every game you must give 100% because if not, like today, in any moment the game can change.

"After the sending-off it was very difficult."

Mancini had no complaints about Kompany's dismissal and was glad to come through the contest without any of his players sustaining injuries ahead of Wednesday's Champions League trip to Villarreal.

Wolves manager Mick McCarthy - whose team are now winless in eight league games - refused to criticise Hennessey, but was disappointed that an error had led to Wanderers falling behind.

"He was fabulous, some of the saves he made in the first half were just outstanding," McCarthy said. "He has been brilliant all season and there will be no recriminations from me on his part.

"But it is another mistake which has let the opposition get the lead, and we had been doing okay."