Winger Cristiano Ronaldo reckons he plays his best football only when he is booed by the fans in the stands.

The Manchester United winger has been the subject of opposition fans who boo him whenever he touches the ball due to his involvement in getting Wayne Rooney sent off at World Cup 2006.

Ronaldo said: "It's normal for me now. If it doesn't happen, I'm thinking, ‘Why aren't they booing?'

"It's part of football. Maybe they think if they boo I'll lose my concentration - but it doesn't happen because I like it."

The Portuguese was also adamant that although he has been voted the best player on the planet in 2008, there is still more to come.

"I've improved every year and the last season was the best. But I want more - this season I want to score the same amount of goals, or more. I know it'll be hard but I think it's possible."

Ronaldo was also quick to add that he has sought advice from players who have done it all to see how they coped with handling the pressure and fame of the game.

"I've spoken to players who have a great history in the game. They've told me it's not what you do in one season, it's staying at the top level that is the challenge.

"If I don't perform, people will start to criticise me and I don't want that. I'm ambitious and plan to win many more things.

"When I arrived at 18, I was a good player, but not in decision making, like whether I have to pass the ball or dribble.

"Winning trophies and being at this club gives you maturity and I've learned a lot. When you're playing around great players you learn."

Ronaldo has scored 14 goals this season but Sir Alex Ferguson wants all his four strikes including Wayne Rooney, Dimitar Berbatov and Carlos Tevez to hit the 20-goal mark by the end of the season.