Cristiano Ronaldo claims Chelsea have not improved this season despite the arrivals of Michael Ballack and Andriy Shevchenko.
The Portuguese winger says Chelsea are 'about the same as they were last year' and 'just do enough to win' games while Manchester United have got better.
He even claims that this United team can emulate the side of 1999 and win the Treble.
"I think we're capable of winning everything - the Premier League, FA Cup and Champions League," Ronaldo told Zoo magazine. "Man United are fighting, as always, to win every trophy.
"This weekend's game with Chelsea is very vital. We're neck-and-neck with Chelsea and this is a good sign because we can't allow them to go too far ahead like last year. We're in a better position to win the league.
"Rivalry between us and Chelsea exists and I've experienced it in each match we've played. But there isn't the same passion as the Manchester derby or games against Arsenal or Liverpool. Perhaps it's because now they are doing well, whereas before it had always been United at the top.
"I think Chelsea are about the same as they were last year. The transfers of Shevchenko and Ballack haven't changed them too much in terms of their superiority to everybody else. They have to work harder to win games. They just do enough to win."
Ronaldo also reveals his petulant and destructive side in the magazine interview.
He said: "Sometimes when I perform badly or when things don't go the way I want, I come straight home, go to the small bedroom in my house and lock the door. I just stay there.
"I also have boxing gloves to hit something - or someone - to relieve stress. And I like to play the jambe, which are bongo drums, because it feels good. And I have a dartboard where me and my friends have competitions.I play football in the garden, like loads of guys do.
"I even broke a window once. I made a pass to my cousin Nuno but the ball hit the glass and broke it.
"I have always been destructive! When I was mad once, I put a TV set in a tree and tried to take it down by kicking a football at it. And it worked!"