Rooney questions Blues confidence

Rooney started the Champions League win over Sporting Lisbon

Manchester United striker Wayne Rooney says Chelsea's title hopes could be fatally damaged if they lose Sunday's Premier League game at Old Trafford.

"If we can win, that would be Chelsea getting one point from nine in their last three games," Rooney told MUTV.

"You never know what that might do to their confidence," added the striker, who was speaking before Jose Mourinho's departure from Stamford Bridge.

"A chance to go three points in front of them makes it a massive game."

Rooney fractured his foot in the opening-day draw with Reading, but the England international is set to play his second Premier League game of the season on Sunday.

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The United striker started for Sir Alex Ferguson's side in the midweek Champions League win over Sporting Lisbon.

"You have to regard Chelsea as the main threat," added Rooney, whose side lie fourth in the table, two points adrift of Arsenal but level with Chelsea.

"They have won two titles out of the last three but they have had a difficult start because, like ourselves, they have had a lot of injuries.

"It will be a lot tougher this year anyway because clubs like Everton and Tottenham have really good squads now.

"Liverpool will be up there and Arsenal have had a fantastic start. We just have to keep plugging away."