John McEnroe, whose temper tantrums are the stuff of Wimbledon legend, today called on Andy Murray to control his anger if he wants to win the biggest prize in tennis.

McEnroe's clashes with officials became a central part of his tennis persona but the former Wimbledon champion now accepts it was largely counter productive.

Murray's petulance was a feature of his time with ex-coach Brad Gilbert, the vastly-experienced American who took Andre Agassi and Andy Roddick to No1 in the world rankings. Gilbert was often berated from the court by his player but he has been replaced by Team Murray, a group of coaches and fitness experts, and the British No1 seems to be aiming his frustrations at himself these days.

The 21-yearold has been letting off expletives courtside and he will be under even more scrutiny for such behaviour during Wimbledon.

McEnroe will be watching closely as a key member of the BBC commentary team and said: "It all depends how you let that anger out and it can become a case of diminishing returns.

"It inspires some people, and it could help Andy at times, but I have also seen it hurt him."

He is encouraged by Murray's insistence that he can win Wimbledon and this mindset should serve him well, despite Roger Federer's obvious domination of the game on grass.

"It's good that Andy is saying he can win," said McEnroe. "It's going to be a tall order for him but he is there as one of the contenders and I don't see a lot of guys in that position.

"To be honest, I don't see Roger losing even though Rafa [Nadal] has put him on the ropes at times."