Reigning champions Manchester United have taken pole position in the title race in recent weeks, and Mancini feels his squad depth has let them down.

Despite spending over £200 million since taking charge two years ago, the Italian wants more investment.

"We lost Yaya and Kolo Toure for the African Nations Cup, had some injuries and lost Vincent Kompany, Joleon Lescott and Sergio Aguero in the last two games," bemoaned Mancini.

"Maybe next year if we lose two important players, we can have another two good players and we can change.

"Up to now, we have plugged away at building a strong team, so now I think three or four more players with a strong mentality will be enough to finish it.

"The difference is in 20 players, not the 11, and because they are used to staying on top, they play without problems.

"We maybe need time - but we have already arrived as one of the best teams in Europe.

"The difference with United is in their squad, not their starting eleven. Because they are used to always being at the top they can play without problems and they don't have the pressure we have, because they have won everything.

"When you play against a team like United, that is the difference - not the players."