But after Sergio Agüero equalised from the penalty spot, Samir Nasri struck an 86th minute winner following a decisive intervention from Tévez, whose one-two with the French midfielder created the opening for the goal.
And six months after declaring Tévez to be 'finished’ at the Etihad Stadium following his actions in Munich, Mancini admitted that the former Manchester United forward can now be a key figure in the title battle against Sir Alex Ferguson’s league leaders.
“Carlos is not 100 per cent.” Mancini, the Manchester City manager, said. “This is normal, but he knows football and it was important because he did an incredible assist for Samir.
“I think that Carlos needs time. It is not easy for him, but it is important that, now he is here, in ten days or two weeks he can find good form and be important to us.
“I have spoken with Carlos every day in the last six weeks. He knew he would be on the bench in this game and probably did well to play for more than 20 minutes.
“He is an important player, though, and he needs another two the three weeks to get good form for the future. But when he plays, he knows where he should take the ball.”
Despite apologising for his behaviour this season since returning from an unauthorised three-month trip to Buenos Aires last month, Tévez was afforded a mixed reaction from City fans while warming up.
He was also booed by a minority when he replaced De Jong, but Mancini insists that the time has come for the supporters to draw a line under the past. Mancini said: “This was finished a month ago. When Carlos came back, it finished everything.
“It is important for him to play games — for us, for him and his future.
“I think it is important that, in the end, he made an important pass for Samir and all of the supporters were happy for this.”
City’s victory moved Mancini’s team to within one point of United at the top of the table. With City travelling to Stoke on Saturday evening, 48 hours before United face Fulham at Old Trafford, they could reclaim top spot by avoiding defeat at the Britannia Stadium.
But despite admitting that the form of his team has not been impressive in recent weeks, Mancini insists that two second-half fightbacks in the space of a week — City overturned a 2-0 Europa League deficit to win 3-2 against Sporting Lisbon last Thursday — has proved the strong mentality of his players. Mancini added: “I think we have played fantastic football at times, but so-so in the last month. But after tonight, maybe things can change. If you are not in good form, you can’t win the last two games in the second-half, so that shows our confidence is good. I was frustrated that we didn’t take our chances in the first-half, though.”
Mancini, who joked that he felt it was 'squeaky-bum time’ when Chelsea took the lead, replaced in the ineffective Mario Balotelli with Gareth Barry at the start of the second-half in an effort to trigger a response from his team.
He said: “I didn’t like how he [Balotelli] played, so I made a tactical sub. Only this. Did Mario understand? Why not? Yes.”
Roberto Di Matteo, Chelsea’s caretaker manager, said: “It’s a setback for us for sure, but not so long ago we were seven points behind third place. Now we are six points behind third place so we need to look at these things. We are going in the right direction.”
