Lleyton Hewitt signalled his belief that he is building up for his most convincing Grand Slam challenge for a couple of years when he enjoyed an emphatic win in a battle of former world number ones against Gustavo Kuerten.

The battling Australian's 6-3, 6-4 victory over the popular Brazilian carried him into the last 16 on Wednesday and suggested that he has a good chance to push on to his first Masters Series final for 17 months.

Hewitt would relish that, given that he has had to endure constant questions that his career has been derailed by a long-lasting court case with the ATP, the governing body of the men's tour.

It was here in Cincinnati that it all began two years ago when Hewitt was fined for declining an interview with ESPN before the match, but there was no evidence of that bitter memory in his performance on Wednesday.

When Kuerten started with two double faults in his first three service points, Hewitt took advantage to gain a stranglehold on the match.

He broke serve immediately, consolidated it with a game in which he created a delicious cross court drop shot winner from a deep position, and dropped only one point in four service games to take the first set.

Hewitt was faster, more confident and more consistent than Kuerten, who showed signs in Toronto last week of having benefited from missing Wimbledon to rehabilitate his hip, but was submerged by the energy of the younger player.

The match was effectively over when Kuerten dropped serve again in the third game of the second set and Hewitt concluded his day's work with hopeful words about the U.S. Open, his breakthrough tournament when he became champion three years ago.

"I am winning matches so I am doing something right I suppose," he said.

"Since the U.S. Open last year I have felt like I have been playing pretty well and I feel like my game is not far away.

"I shall be here (the United States) for six weeks trying to build myself up," Hewitt added, explaining his decision to miss the Olympics. "So I hope that I will be playing my best level."