The Italian believes his side lacks the necessary experience to win the Champions League, but still expects big performances from his men in their remaining group games
The Premier League champions currently sit bottom of their group, labelled by many as this season's infamous 'group of death', after losing to both Real Madrid and Ajax and scraping a draw against Borussia Dortmund.
And with chances of qualication for the latter stages now looking extremely slim, the 47-year-old manager has confessed that he doesn't believe his side has what to takes to be a competitive Champions League outfit yet.
"I don't think we're ready to win the Champions League," he told The Guardian.
"If we say we're ready to win it, we're not honest. In the Champions League it's clear that incredible situations can happen in February and March but we've been drawn in a tough group this year, like last year.
"We're a good team but we're not ready in the Champions League, like the other teams. Chelsea tried for 10 years to win the Champions League. They were probably the best team in Europe for 10 years and they won it [last May] after 10 years, probably when they didn't deserve to. They deserved to win it three or four years before."
Yet despite the seemingly impossible task faced by Mancini and his troops, the Italian still expects the players to go all out in order to collect nine points from the three remaining games.
"The players owe me three big performances," he added.
"We have less chance of qualifying for the next round but, when you're a top team, even when you're out, you should play 100% in every game.
"We have three games left but we are only focusing on Ajax. There's no mental problem [in the Champions League]. The players are the same and the referees are the same. We just need to improve. I will change nothing."