A revitalised Tevez has helped fire City back into contention for the Barclays Premier League title after returning to the starting line-up for the last three games.
City have won each of those games, with Tevez scoring four in the process, to cut Manchester United's lead at the top of the table to three points ahead of Monday's eagerly-anticipated derby.
The six months Tevez spent out of the side during his infamous dispute with the club may not have been forgotten but Mancini is concerned now only with getting the best out of the Argentinian.
Mancini said: "Carlos is not 100%, because it is impossible for him to be 100% after six months without playing.
"But he has experience, he is a clever player. He has scored four or five goals and this is important."
When asked if he felt Tevez had played better than expected since his return, Mancini said: "Probably, yes - but I hope in the next three games he continues to do this.
"It is difficult after six months without football to play at this level."
During his stand-off with City, Tevez spent more than three months on unauthorised leave in Argentina but Mancini does not wonder what might have been had he been available during that time.
It has been suggested that with their top scorer for the past two seasons in harness, City, who led the table for much of the season, might have won the title by now.
Mancini said: "No, I don't think (about) this.
"It was a strange situation six months ago and I said to Carlo, a lot of times, apologise and it would be finished.
"Carlos didn't want to do this, he wanted to leave the club in December.
"But if we are here it is also because the other players were playing very well.
"(Sergio) Aguero scored a lot of goals, (Edin) Dzeko the same, (Mario) Balotelli, all the team played well.
"If not, it is impossible we would be here at this moment."
Tevez, who has also made four substitute appearances since returning from Argentina, is yet to complete 90 minutes despite making such an impact.
Mancini said: "It is difficult for him to play after six months.
"For this reason he played only the last two or three games.
"I think he can find his best form next season, after pre-season."
When asked if that meant Mancini wanted to keep Tevez, who is widely expected to leave in the summer, the Italian - not for the first time - was coy.
He said: "I think he has a contract with Manchester City, but I don't think in this moment it is important to talk about the future for everyone."
While Tevez is enjoying a new lease of life, City's other headline-grabbing striker Mario Balotelli is hoping to force his way back into the action.
Balotelli has missed the last three matches through suspension after being sent off in the loss at Arsenal earlier this month.
With that merely being the latest in a long line of misdemeanours, the 21-year-old's future at the club was thrown into doubt.
But Mancini has not ruled out recalling his fellow Italian for Monday's crunch clash, which could see City return to the top with two games remaining with victory.
Mancini said: "Mario is a player like the other players. He is available for Monday and after we decide.
"In one game Mario can do everything. He can score two or three goals if he decides this. This is the manager's problem."
Mancini has previously said he cannot trust Balotelli but thinks he could in such a big game.
He said: "I think in this game yes - only in this game!"