Andy Murray is not short of admirers. His opponent at the US Open today, Jurgen Melzer, is well aware of what he is up against but Murray also received praise - when Pete Sampras's former coach Paul Annacone tipped him to be a challenger to the likes of Rafael Nadal, Roger Federer and Novak Djokovic.

Andy Murray is not short of admirers. His opponent at the US Open today, Jurgen Melzer, is well aware of what he is up against but Murray also received praise from a more illustrious source yesterday when Pete Sampras's former coach Paul Annacone tipped him to be a challenger to the likes of Rafael Nadal, Roger Federer and Novak Djokovic at the top of the men's game.

According to Annacone, Murray's biggest challenge is the number of options he has at his disposal. It is, as the American points out, a nice problem to have and one which Sampras himself struggled with as a young player.

"Andy can do so many different things at such a high level. For him to figure out how to be in the elite echelon and challenge for grand slam titles, all he has to do is figure out how to manage his game," said Annacone, whose crowning achievement as a coach was helping Sampras win his fifth US Open title in 2002 and a record 14th major trophy.

"I wouldn't want to compare Andy to Pete yet, but Andy's a great player. When Pete was younger he grew up as a baseliner. He moved so well and he used his backhand really steady and had a great running forehand.

"Then all of a sudden in his later teenage years the serve fell in to place and he thought: Wait a second, maybe I should come in, maybe I should stay back'. It becomes a little bit complicated, so part of the maturation process is figuring out how to do that.

"It's a nice problem to have when you have those options. But if you saw him in Toronto and Cincinnati this summer Andy managed it pretty well. If he gets consistent like that, the Nadals, Federers and Djokovics of this world are going to have another guy to deal with week in and week out - they probably have already."

When Sampras retired, Annacone went on to coach Tim Henman but his current job, as the Lawn Tennis Association's Head Coach of Men's Tennis, means that he takes a special interest in Murray's progress. Annacone is also coach to Great Britain's Davis Cup team and was alongside team captain John Lloyd yesterday when they named Murray and his brother Jamie alongside Ross Hutchins and Alex Bogdanovic in the team for next month's relegation play-off against Austria at Wimbledon; with Murray and Melzer appearing destined to meet again. Lloyd and Annacone will be watching today's encounter with interest.

"I like the match-up on this surface or on grass," said Lloyd. "Andy came through a tough match against Michael Llodra in the last round and he has that ability to sometimes look like he's not playing at his best but he gets through. I'm very confident that he'll win."

Melzer, 27, who is ranked 48 in the world, is well aware of the dangers posed by the Scot, while his confidence will be dented by the knowledge he has been in the third round of a grand slam eight times without progressing. "Andy is a very dangerous player and a very different player from many of the other players on the tour," said Melzer.

"When the ball is in your side of the court, his body language suggests that he does not have much energy. But when the ball is on his side, he bursts into action and covers the court extremely well.

"He tries to make you fall asleep by playing lots of very long rallies. Hopefully, I won't fall asleep against him . . ."