Sir Alex Ferguson has challenged Rio Ferdinand to play better as the defender may be axed for both Manchester United and England.

Ferdinand displays have come under criticism after a string of errors recently, which have led to speculation that the Man United centre-back could be on the decline.

The England international gave Craig Bellamy his chance to score in the Manchester derby in September and a major mistake of his led to England custodian Robert Green seeing red against the Ukraine in October.

The veteran defender was once again criticized on Sunday when he was overmatched in strength and speed by Fernando Torres as the Spanish striker blasted the ball past Edwin van der Sar for Liverpool's first goal in a 2-0 win.

This has led to Ferguson questioning whether Ferdinand is playing well enough to warrant a place in the England team bound for South Africa in the 2010 World Cup.

"He has to get good form. That's an important issue for the coach to pick the right team," Ferguson told the Sun.

"In defence you've maybe got more options than other positions. He'll need to get his form right."