Mancini waved away suggestions that the title is already a two-horse race and argued there could yet be a silver lining to City's latest Champions League flop.
"It is difficult to describe it that way, because the season is long and in February, when the Champions League starts again, everything can change," said Mancini.
"Who else can win it? Chelsea, I think. In this moment, I think it is a three-horse race. But we have another 20-odd games to go.
"The finishing line is too far away to say. Last season, in six games, we recovered eight points.
"United are already through in the Champions League. I hope Chelsea stay in it as well, because it could benefit us.
"The Premier League is too long and it would mean they would both play more games and that when the Champions League starts again in February, it could all change in the Premier League."