SPORTS: Roddick,Fernando , del Potro into Washington semi finalss

WASHINGTON: Andy Roddick defeated big-hitting Ivo Karlovicin two tiebreaker sets on Friday to reach the semifinals of the Legg Mason Classic.

Top-seeded Roddick won 7-6 (4), 7-6 (5), with the typical scoreline for two big servers disguising the repeated service breaks.

In other quarterfinals, fourth-seeded Fernando Gonzalez defeated Tommy Haas 7-5, 6-4, setting up a semi against second-seeded defending champion Juan Martin del Potro, who advanced after Robin Soderling withdrew before their match with a right elbow injury.

Playing in his first tournament since losing in an epic Wimbledon final, Roddick is two wins away from his fourth Washington title after overcoming the first two breaks of his serve in six career matches against the 2.05-meter (6-foot-10) Karlovic.

Roddick entered the match with a 4-1 record against the Croatian, who leads the ATP Tour in aces with Roddick one spot behind. Their six previous sets had gone all the way to a tiebreaker, a trend that held in this match, even with both players broke the other's serve twice.

After netting a volley to go down 1-3 in the first, Roddick broke back to get it to 3-4. The action moved to that inevitable tiebreaker, which the American took control of by winning the first three points.

In the second set, Karlovic broke in the opening game, with Roddick hitting a ball out of the stadium in frustration.

His composure returned and after earning his second break, Roddick lost only five more points on his serve the rest of the way, while earning a mini-break to go up 4-3 in the tiebreaker.

Roddick will play the winner of Friday's late quarterfinal between American John Isner and No. 8-seeded Czech Tomas Berdych.

Gonzalez too is playing in his first event since Wimbledon. Tied at 5-5 in the first set, he angled a forehand past the charging Haas for the first break point of the match. He then had three forehand winners in his own service game to close out the set.

``Both of us played really good tennis in the beginning,'' said Gonzalez, who has been dealing with right knee tendinitis.

``I only had one break point and I did it. That gave me a lot of confidence for the rest of the match.''

Gonzalez broke serve to open the second set and again to go up 5-2 against a frustrated Haas. A Wimbledon semifinalist this year, Haas broke back and then held his serve to get to 5-4. But the 11th-ranked Gonzalez rebounded and put away an overhead smash to win the match. The Chilean improved to 5-0 in quarterfinals this year.

``He made two mistakes in the first game (of the second set) and I took advantage,'' said Gonzalez, who reached the finals in Washington in 2003.

Del Potro is hoping the day off following a lengthy third-round match will help him earn his first career victory against Gonzalez.

``I've lost to him three times in my career and I hope I can get my first win (Saturday),'' said the sixth-ranked Argentine, who has picked up five tournament titles since their last head-to-head match in 2007.

``He's a different player now,'' Gonzalez said. ``He's one of the new generation and he's had really good results the past year. But, it's better to have a positive record when you (next) meet.''

Soderling, a finalist at the French Open, was expected to have his elbow scanned on Friday.

``My elbow started to bother me two weeks ago and this morning it was really sore,'' the Swede said, adding that he hopes to play one or two tournaments before the U.S. Open.