Del Potro still has a way to go to reach the top

Juan Martin Del Potro could be the ultimate tennis player. He has all the physical attributes and the ruthless killer instinct to succeed. And a long way to go.

The powerful Argentine aspires to be the best player in the world and there are plenty of good judges who expect he will achieve his goal, perhaps sooner than he thinks.

He is already on his way. He beat Roger Federer in last year's US Open final to claim his first grand slam title and is ranked fifth in the world.

"It looks like del Potro is the man at the moment," Patrick Rafter told reporters today. "He's got an all-round game, he's a complete player and players don't like to play him."

Rafter would be unlikely to find too many people to argue with him although Del Potro was prepared to take issue with the Australian.

"I don't know. He knows about this sport but I don't want extra pressure," Del Potro said.

"I have too much pressure with me. So thank you Patrick, but I have a long way to be the next number one or to be better."

Despite carrying a wrist injury and playing below his best, Del Potro is proving to be a formidable obstacle to anyone in his path at the Australian Open.

He won an epic five-set match with the American James Blake in the second round on Wednesday then was back at it again on Friday, beating Germany's Florian Mayer 6-3 0-6 6-4 7-5.

He did suffer a worrying lapse in concentration in the second set but regained his composure to finish off his opponent in two and a half hours and ease into the fourth round.

"Today, especially in the second set, I felt very confused with my game," he said.

"But I improved a little bit and in the end I finished the match playing some very good points.