After a dramatic title victory last season, Mancini’s men have struggled to keep pace with a remarkably consistent United, and could only put one goal past a struggling Aston Villa on Monday evening.
And with City having scored 17 less goals than United over the course of this Premier League campaign, Mancini believes the reason for their struggles is no secret.
"At Southampton, we played very well and we lost 3-1," the Italian told reporters. "We had other games like the one at Villa - against QPR and West Ham - where we missed four or five incredible chances."
He added, "Even in the Villa game, we had other chances to close out the match rather than winning 1-0. It has been our problem this year and has cost us points. We have a lot of chances in every game that we are missing. This is the difference at this moment."