Manchester United boss Sir Alex Ferguson admits there's no limit to what Cristiano Ronaldo can achieve in the game.

Fergie said: "Who's to say he can't get many more hat-tricks for us. The way he is going, who is to say where he will finish up.

"He is improving all the time. A haul of 22 goals already is marvellous.

"We said in the summer: 'Could he do it again?' I couldn't see why not.

"He is an improving player. He is showing more maturity. His decision-making is getting better all the time. His knowledge is getting better."