The Argentine striker's career at City looked to be over after he refused to leave the bench to warm up against Bayern Munich in the UEFA Champions League last season, and he did not play for more than five months after being placed on leave by the club.
The forward returned to the fold to help City's title push last season, though, and he is now in fine form and fitness.
"Carlos [Tevez] is a top striker, one of the best in the Premier League," Mancini told reporters. "My relationship with Carlos is good. I am happy with the way we handled [Munich]. When we started the season this year he was serious and working well for the first time after four or five years.
"I was happy with his work in preseason. These days we don't talk about what happened in Munich. We have talked enough."
Tevez has been in excellent form for the champions this season, and his goal against QPR earlier in September ensured he was the first ever Manchester City player to score 50 goals in the Premier League. Mancini will need Tevez's talents if City is to get through a tricky Champions League group, in which it has been drawn against Real Madrid, Borussia Dortmund and Ajax.
"Things haven’t changed. [Tevez] is still a top player and will be important for us," Mancini said. "[Dortmund] is very good on the counter attack and we expect a very difficult game – it's a really tough group. We want to go to the second stage this year, so it's important we do well against Dortmund. They are probably our main rivals to qualify. But don't forget they only beat Ajax in the last minute."