Although Rooney was speaking before Jose Mourinho's shock departure from Stamford Bridge, he has noted the Blues' return of just a single point from their last two matches.

Another defeat this weekend would really leave Chelsea floundering and provide new boss Avram Grant with a major headache in his first few days in charge.

"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.

"I know we didn't have the best of starts this season but it is amazing how quickly it has turned round.

"Now we have a chance to go three points in front of them, which makes it a massive game, even if it is not going to decide the title."

Currently fourth and fifth in the Premier League standings respectively, United and Chelsea are both looking to keep pace with early leaders Arsenal.

Yet, while he expects the Gunners to keep going and Liverpool to put up more of a fight than they have done in recent times, Rooney, set to start his second game on the trot following an eagerly-awaited return from a fracture foot sustained in the opening-day draw with Reading, still expects Chelsea to be the team United have to finish above this term.

"You have to regard Chelsea as the main threat," he said.

"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 and picking points up."