The Rossoneri have only lost once in Serie A since late September and many feel they have momentum on their side despite still being six points behind their rivals in the table.
Mancini told Gazzetta dello Sport: "It's impossible to say it, but Milan have the chance of a lifetime. They are doing very well, while Inter seem to have been treated badly a little.
"I don't think that the winner of the derby necessarily wins the Scudetto. In my opinion anyway Inter will win it again."
Mancini also had praise for Ronaldinho, a player with whom City have often been linked, who is finally rediscovering his best form.
"I had faith in the fact that Leonardo, as a Brazilian, could connect with him. And that's what has happened. You see that it has been like a mental click. And it also seems that Borriello is moving well."