Sydney  - Australian legend John Newcombe has voiced concern at the current state of Roger Federer and Rafael Nadal, tipping Andy Murray as an outside chance to win the Australian Open.

While Federer, Nadal and Murray compete this weekend in an exhibition in Abu Dhabi, it's the young Scot who has caught the attention of former great Newk.

"He got to number four in the world but the way he was playing at the end of the year, you think in 12 months time he'll be close to number one, " the seven-times Grand Slam champion told Australian media.

Newcombe is concerned by the knee injuries which forced Nadal to end his season early last November, missing both the Masters Cup and Davis Cup final.

Federer is trying to regain traction after winning just one major in 2008, though he does stand within one victory of the record of 14 on the all-time list held by Pete Sampras.

"How will Nadal's injuries go - with his knees? With Roger, I'm sure he's been doing some very serious training and realising he has to come up with something a bit extra, which sounds strange, but (he needs to) vary his game and come to the net a bit more.

"The way they finished last year, I wouldn't be surprised to see Andy Murray - In my mind, he could be the guy that will step up and win."

Newk also has his doubts on Melbourne Park holder Novak Djokovic. "Let's see how he handles the nerves when he's defending his Grand Slam title." (dpa)