Manchester United boss Sir Alex Ferguson says Wayne Rooney needs to improve his finishing if he is to become the best in the world.

Even the 25 goals Rooney has scored so far have not been enough to earn the England striker unreserved adulation, with Ferguson insisting he must learn from Ruud van Nistelrooy, Andy Cole and Ole Gunnar Solskjaer if he is to become the perfect player.

Ferguson said: "Where I hope he improves is with his predatory instincts in the penalty box. He's done great this year. But he has still got to get to the levels of Solskjaer and Cole and Van Nistelrooy. If he got to that level, he'd be the best in the world.

"I think a lot about energy and how that should be channelled in the right way, and Wayne should be [playing] through the middle.

"Yes, sometimes he drops in there, it's a natural thing at times. I don't have a problem with that but his great energies - desire, purpose, courage - all the great strikers, Denis Law, John Charles, had that courage to be in there, take the hits and score the goals .

"I know there's more to be developed, and I know he can do that."