Dietmar Hamann hails Robin van Persie's impact at Manchester United

Dietmar Hamann believes that Robin van Persie has been the main difference between Manchester City and Manchester United this season.

The Dutch striker, who joined United from Arsenal last summer, has scored 16 goals in 21 Premier League appearances so far.

"You wonder how much closer City would be if he was playing for the other team in Manchester," he told the BBC's Football Focus programme.

"I wasn't too sure about him when United signed him. He cost a lot of money and he's 29.

"But he's made a big impact and he could be the difference in the title race."

United are currently seven points clear of City at the top of the league table.