Pete Sampras believes Andy Murray has what it takes to win a grand slam singles title and says he is "only one notch below" world top two Rafael Nadal and Roger Federer.

Murray, 21, enjoyed a prolific season, reaching number four in the world and beating Nadal en route to the US Open final in September, only to lose out to Federer.

That followed a run to the quarter-finals at Wimbledon, which included a thrilling five-set defeat of Richard Gasquet, and a Murray major win is widely considered to be only a matter of time.

"He's moved himself right up to one notch below Roger and Nadal," said Sampras, who is in London for the first time since 2002 for the Tour of Champions' BlackRock Masters.

"He's right on the edge of breaking through and winning a major. He's got the game.

"The US Open was a great breakthrough for him and I'm impressed.

"He's competitive, he's a great mover and he's got a ton of talent. He's definitely got the game to win a major."

Sampras, who won a record 14 grand slam titles - seven at Wimbledon - before retiring six years ago, says the key to Murray winning a maiden grand slam is psychological rather than any physical aspect of his game.

Sampras said: "He needs a bit more self-belief and confidence that he can win a major.

"Watching the US Open, I could sense that he didn't really believe he could win that match.

"But he's right there ready to break through and he's only 21 so he's got many years to keep it together.

"He'll do it, I really believe that. He's the real deal."