Roberto Mancini has spoken of his belief that Carlos Tevez is "destined" to be the central figure in the most important Manchester derby ever staged and score the goal that helps to decide the title race.

Mancini goes into the game at the Etihad Stadium on Monday night having dropped his assertion that Manchester United cannot be caught and apparently convinced that the decisive moments will come from a player who has spent most of the season at loggerheads with his manager.

Tevez's relationship with Mancini appeared to have broken down irretrievably after the infamous Champions League tie at Bayern Munich in September, followed by the Argentinian's disappearance back to Buenos Aires. In total, Tevez has forfeited in excess of £10m this season in fines, lost bonuses and withheld wages but the striker is back in the team, having been unable to force a transfer, and Mancini's belief is that the former Manchester United player is about to write another chapter into an already remarkable story of occasional brilliance mired with frequent controversy.

"I think Carlos is destined to score the most important goal in the history of this club," Mancini said. "This is my belief."

This was the first admission from Mancini that, contrary to what he had said previously, United are in danger of blowing the title in the wake of their defeat at Wigan Athletic and the 4-4 draw against Everton at Old Trafford seven days ago. Sir Alex Ferguson's team hold a three-point lead but City's goal difference is six better off, meaning they will go back to the top of the table if they beat the champions.

Mancini's singling out of Tevez also supports the theory that the manager will not risk starting Mario Balotelli, who is available after suspension. "The problem with Mario is that he can get a red card at any moment on the pitch, in the tunnel or even in the dressing room," Mancini said.

After the derby City still have to go to Newcastle United to face a side chasing a Champions League qualification place and then end their season at home to Queens Park Rangers, who are fighting against relegation. United have two games against mid-table teams, at home against Swansea City followed by a trip to Sunderland, and Mancini maintains Ferguson's team will find them "easy" to win.

However, he also believes that if City clinch their first league title since 1968 it will usher in a longer period of dominance for the club. "We don't just want one championship. I want to leave a legacy. That's how I want all the City supporters to remember me. I could be wrong, but I think Manchester City are set up now to win many trophies in the future. That has to be the target."

No longer sticking to his line that the league was "finished", Mancini was asked whether catching and overhauling United would signal a shift in power at the top of English football. "If you win the title there can be no debate about who is the No1 team in Manchester. For this year, at least. United have a fantastic history and it is impossible to change that but, for us, our targets should be to match the achievements of United, Barcelona and Real Madrid. Even if we don't win the title this year that will not change. And I think the team that starts next season will be stronger than the one that finishes this season because of the experience."

Mancini has been assured that he has the backing in Abu Dhabi to continue next season, reinforced last week by a rare public statement from the club's owner, Sheikh Mansour. "Even if he hadn't said it I was relaxed about my position anyway," he said. "I think the Sheikh and [the chairman] Khaldoon [al-Mubarak] are happy with what we have done this season."