Mancini's reasoning is that City require more experience at this level before they can truly compete for the greatest prize.
"Chelsea tried to win Champions League for 10 years," he said. "In the best moments, when Didier Drogba was young, they didn't win.
"They did it last year when no-one thought they could.
"We need to improve our team because there are a lot of teams better than us.
"I am not saying if you get to February you can't win. Anything can happen. But we didn't do that."