After six months out following his major fall-out with Mancini and the City hierarchy, Tevez came off the bench on Wednesday night to inspire a 2-1 comeback triumph over Chelsea. He was involved in the early stages of the attack that brought the hosts level thanks to Sergio Aguero's penalty and played the pass for Samir Nasri to net the winner.
"Carlos is not 100% but that is normal," said Mancini. "But he knows the football. That was important because he did an incredible assist for Samir."
He added: "What happened with him finished one month ago when Carlos came back and everything was finished. I have spoken to Carlos every day in the last month.
"He knew he would be on the bench today and would probably play for 20 minutes. If he can find good form in 10 days that would be important for us. Now it is important for him to play some games, for us, him and his future."
Chelsea's first defeat under Roberto Di Matteo is a blow to their hopes of securing a top-four finish to squeeze into next season's Champions League.
"It is a setback for us but we look forward to the future," said Di Matteo.
"Two weeks ago we were seven points behind third place, now we are six.
"We need to look at these things because we are going in the right direction.
"We showed we can match the best teams in this league."