The midfielder was given his marching orders just before half-time after appearing to headbutt Norwich defender Sebastien Bassong following a strong tackle by the latter.

Nasri will now serve a three-match ban – unless the club protests the red card - which includes City's trip to former side Arsenal on January 13, but Mancini was adamant the Frenchman was innocent.

"It was not a red card. It was not a red card," he told Sky Sports.

"I can't understand why the linesman told the referee it was a red card. Samir did nothing.

"It changed the game. We would have won the game no problem, but with 10 players it was difficult. Norwich is a good team.

"But today we showed that we are there for the title because we (showed) fight."

City were two goals to the good after just four minutes thanks to a double from Edin Dzeko, but a resilient Norwich side battled throughout before eventually succumbing to a 4-3 defeat.

Mancini was pleased to get back to winning ways after the 1-0 loss to Sunderland, but reiterated his belief his team deserved all three points on Boxing Day before dismissing the seven-point gap between themselves and title rivals Manchester United.

He continued: "We played well and deserved to win (against Sunderland), we just failed to score. It is like that every year at Sunderland, we have 21, 22, 23 chances to score, and we don't score. But, that is in the past. We won today.

"It is not important to look at the table. We just need to work, win and win many games in the row. Then we can look at the table in February."

Norwich counterpart Chris Hughton defended Bassong for his actions but lamented a third consecutive loss in the festive season, despite his side's endeavour.

"We conceded poor goals but Manchester City showed the quality they have got," Hughton said.

"They have spent a vast amount of money on quality finishers but you cannot expect to be 2-0 down and have a good day.

"At 4-3 we showed a lot of character and it felt like one of those which might end up going our way. I can't fault the character and the endeavour.

"On the sending off, there was certainly a coming together of heads and certainly a movement from Nasri. Whether that was enough to have a sending off I don't know.

"The referee obviously thought it was. Although there was a coming together, certainly from Seb there was no movement."