London:Ashley Cole suffered what looked a serious knee injury as Chelsea remained within six points of Manchester United at the top of the Premiership table. 

The England left back was stretchered off 10 minutes into the second half Wednesday when Chelsea won 3-0 against Blackburn, after catching his studs in the turf, his leg buckling horribly beneath him.

"It looked bad, but we will have to wait," manager Jose Mourinho said.

"We will know (how bad the injury is) in a couple of days,"he said.

A Cristiano Ronaldo penalty, a Lloyd Doyley own goal and strikes from Henrik Larsson and Wayne Rooney gave United a 4-0 win at home to Watford.

Charlton remain second bottom, but closed to within two points of safety as they drew with Bolton, while a goal from Ashley Young on his debut could not prevent Aston Villa going down 3-1 at Newcastle.