While winning the FA Cup would bring City handsome consolation after their apparent failure to defend the title, a review of why they have failed to achieve their prime objectives will still be undertaken.
Mancini feels City proved with their defeat of United they are capable of challenging for title glory again next season.
Mancini said: "We need to continue to play like this for next season.
"We have two or three months where we can work well, where we can improve our team.
"I think we showed tonight we can't be 15 points behind.
"But we can say United won a lot of games. They lost their last game against Norwich a long time ago and they deserve to win this title, for sure."