West Ham United boss Sam Allardyce says Robin van Persie can make the difference for Manchester United this season.

Van Persie struck the only goal of the game last night.

And with the championship already looking like a two-horse race as Chelsea crumble, Allardyce thinks Van Persie could be a decisive factor.

"Manchester United have lots of players who will have good spells and can come up trumps when they need them to," said Allardyce.

"Robin van Persie is a quality player and we have largely kept him quiet.

"But he will score 20 goals for Manchester United, maybe 30. In the end that is normally the difference."