From the BBC:

Tennis legend John McEnroe believes new coach Brad Gilbert can help Andy Murray achieve "great things".

Murray, 19, beat world number one Roger Federer last week and has broken into the world top 20 for the first time.

McEnroe told the Merrill Lynch Tour of Champions website: "Great things can happen if they find common ground.

"Gilbert's got a lot of credibility because the two people that he's coached - Andre Agassi and Andy Roddick - both reached number one."

McEnroe added that the fact that Gilbert has agreed to coach him should be a boost to Murray in itself.

"He's smart - he picks talented guys. I think that says something about Murray that Gilbert's decided to work with him," said McEnroe.

"It also says to Murray that Gilbert believes he can be at the top of the game.

"Murray's made a lot of headway - it's a question of how his and Gilbert's personalities mix as time goes on."