SAN JOSE (California), March 2: Lleyton Hewitt, in one of the most impressive serving displays of his five-year career, fired 16 aces to beat American Todd Martin 6-3 7-5 on Friday and reach the semifinals of the $400,000 San Jose Open.

The world number one now meets fourth-seeded American Jan- Michael Gambill, who ripped 58 winners past Australian Wayne Arthurs to win 7-5 6-7 (5-7) 7-6 (7-4).

Australian Hewitt looked sluggish in his previous two matches but this time he showed off his quick feet, low returns and excellent placement with his serve.

“He served better than almost anyone I’ve played,” said Martin of his 5-foot-11-inch opponent, who doesn’t own one of the tour’s fastest serves.

“He hit the lines with regularity and that’s the most important thing we do out here. Lleyton can’t hit his serve more than 120mph but when it comes down to winning, it’s where you hit the ball, not how hard you hit it.”

Hewitt was playing in only his third match since January 15, when he was beaten in the first round of the Australian Open while nursing chicken pox.

Hewitt said he broke through the pain barrier. “I’ve got through three tough matches and feel I’ve got better and better in each match,” he said.

“To be sitting here in the semifinals is a nice place to be. I never expected to hit the ball well this week and if I come through to Sunday, it will feel terrific.”

At 6-foot-6, the 31-year-old Martin packs tremendous power. But he is not moving as well as he did when he reached the 1999 U.S. Open final and, against Hewitt, was frequently wrong-footed by the cagey 21-year-old.

In the final game, Martin committed two baseline errors to give Hewitt two match points. The Aussie missed an easy forehand passing shot on the first but then Martin dumped a forehand into the net to end the contest.

“Lleyton uses his speed in a very offensive way,” said Martin. “He isn’t able to generate a lot of power off the ground but he cuts off the court so well.

“More than anyone, he recognises which is an opportunity ball and which balls he needs to pay more respect to.”

Gambill and Arthurs played a rapid-fire match, with Arthurs hitting 33 aces to 22 from Gambill.

“It’s very difficult to play someone like him and I served very well,” said Gambill, who has yet to be broken in three matches.

“I knew it was going to be tough. We both played high quality tennis.”

Hewitt and Gambill have faced each other four times, with Gambill owning a 3-1 edge.

“I think Jan-Michael matches up against him better than I do,” Martin said. “He can take slower balls and generate more pace off them than I can.”

Hewitt, who lost to Gambill at Wimbledon 2000 and in the semifinals at Key Biscayne last year, said he did not feel that Gambill had his number.

“He’s a great player and generates a lot of power from the ground and on his serve, plus it’s a little different playing him because he hits with two hands.

“But I feel like I’ve been in every match with him.”

Quarter-final results at the $400,000 San Jose Open ATP Tour event on Friday: (prefix number denotes seeding)

Lleyton Hewitt (Australia) bt Todd Martin (U.S.) 6-3 7-5; Jan-Michael Gambill (U.S.) bt Wayne Arthurs (Australia) 7-5 6-7 (5-7) 7-6 (7-4); Andre Agassi (U.S.) bt Wayne Ferreira (South Africa) 6-4 6-4; Andy Roddick (U.S.) bt James Blake (U.S.) 6-4 6-2.

KOURNIKOVA BEATEN