Tevez, starting successive Barclays Premier League games for the first time in 11 months, scored a hat-trick and Sergio Aguero also netted a fine double as City moved within touching distance of the summit with a 6-1 win at Carrow Road.
But Mancini's position has not budged.
"It is impossible. The title race is finished. It is true," he said.
When asked why he thought so, now that the gap is two points, the Italian playfully retorted: "Two points? The gap is five points. I think now it's too late for us. I am happy because we started to play like we did in the first half of the season."