Manchester City boss Roberto Mancini admits Manchester United's capture of Robin van Persie transformed the title race.

Van Persie has scored 14 times in the league so far this season while the champions' quartet of strikers have managed only 23 between them.

"Robin van Persie is an important player for them," said Mancini. "It's clear that the difference is this. He has changed the situation.

"We wanted him in the summer because we knew he would be an important player. He is totally different from our other strikers."