BEIJING, Aug.2 -- Top seed Andy Roddick blasted 18 aces to defeat Tomas Zib 6-4, 6-2 and storm into the third round of the US$600,000 Legg Mason Classic in Washington on Tuesday.

Roddick successfully landed 61 percent of his first serves to keep his Czech opponent off-balance throughout the one-hour match. He lost only one of 33 first-serve points.

"It's the only shot I was really hitting in the first set," Roddick said of his 12-ace performance. "I was hitting aces and when I was hitting good first serves they weren't coming back.

"I was really pleased with my serve tonight."

In a first-round match, Britain's 32-year-old Tim Henman lost to American wildcard John Isner 4-6, 6-4, 7-6 after losing the third-set tiebreaker 7-4.

Roddick had little trouble with Zib although he had never played the 31-year-old Czech Davis Cup player ranked 151st in the world.

"Regardless of how the other person plays, you have to play to your strengths," said Roddick. "If you start playing someone else's game obviously it's not going to work as well.

"That being said you start studying what shots he likes to hit to what positions, which serves he goes for on big points. That's the stuff you learn as the match goes on."

The 24-year-old Roddick broke Zib once in the first set and twice in the second.

Despite a 38-10 record this year, including 24-6 on the hardcourts, Roddick said he was not yet ready for the upcoming US Open.

"There's definitely stuff I have to work on," said the two-time champion of the Washington tour stop. "I feel like you always do before you hit your groove. You're on the verge of playing well."

Henman, who suffered a knee injury last October and had hamstring problems in January, saw his record fall to 5-10 this year.

Third-seeded Marat Safin had a much tougher time than Roddick, finally beating Jan Hernych 6-2, 2-6, 6-2 to reach the third round.

Also reaching the third round was fifth-seeded Lee Hyung-taik, who beat Russia's Igor Kunitsyn 6-7 (7), 6-3, 6-1. Ninth-seeded Gael Monfils of France, beat Martin Klizan 7-6 (5), 6-4. Robin Haase of the Netherlands beat 14th-seeded Frenchman Michael Llodra 6-2, 6-7 (7), 7-6 (4).

In Carlsbad, California, Sania Mirza used pressure at the net in the third set to pull off a 6-3, 4-6, 6-2 upset of No. 12 seed Shahar Peer on Tuesday in the Acura Classic.

Mirza, a finalist at Stanford on Sunday, beat her doubles partner by going to the net more often than usual in the final set, trying to shorten rallies. The strategy paid off for Mirza, who said she was tired from playing all week at the Bank of the West Classic.

Serbian No. 2 Jelena Jankovic, ranked third in the world, had little trouble in her first appearance, beating American Vania King 6-3, 6-0 in a late second-round.

Seventh seeded Martina Hingis struggled in her first match before claiming a 7-5, 6-2 second-round win over Michaella Krajicek of the Netherlands. Hingis dominated as she got off to a 5-1 lead, but then dropped four games in a row as she began to commit numerous unforced errors.

Hingis reeled off two straight games to take the set before settling down in the second set.

Russian No. 4 Nadia Petrova advanced with a 6-3, 7-5 second-round victory over countrywoman Elena Bovina.

No. 5 Marion Bartoli of France struggled in her second-round match before defeating Japan's Aiko Nakamura, 7-6 (4), 6-1. Bartoli was the runner-up to Venus Williams at Wimbledon.

(Source: Shanghai Daily/Agencies)