LOS ANGELES: Big-serving American John Isner produced the first upset at the LA Open with a 7-6 7-6 victory over seventh-seeded German Benjamin Becker in the opening round on Tuesday.

Isner, who reached his first ATP semi-final of the year in Indianapolis last week, powered down 15 aces before sealing the win in just over two hours on a sun-baked afternoon at the LA Tennis Center.

Eighth-seeded Russian Marat Safin was in early trouble against American Robby Ginepri before recovering to win 3-6 6-3 6-4.

Sixth-seeded American Sam Querrey thumped Uzbekistan's Denis Istomin 6-2 6-0 in the day's final match.

The towering Isner, 77th in the rankings, swept through the tiebreak in the second set 7-3 to extend his career record to 3-0 over Becker, the world number 44.

"I had a good week last week and maybe I was a little bit tired today," the six-foot-nine American told reporters after losing only four points on his first serve. "I played four long matches last week but today was starting off on a good foot."

Isner was heartened to maintain his form after being sidelined from the game earlier this season for just over a month while struggling with mononucleosis.

"It's done now and I've just to get in a little better match shape," the 24-year-old said. "When you take a month off and don't do anything, you lose a lot"

Former world number one Safin, playing on the ATP circuit this year for the last time, was delighted to beat the winner of last week s event in Indianapolis

Mercurial Russian:

"Robby is playing really well," the mercurial Russian said. "He is a tough player and it was a well-played match from both of us. I was able to go up a break at the beginning of the second set and that helped me to turn the match around."

Fifth-seeded Russian Igor Kunitsyn eased into the second round with a 7-5 6-2 victory over Indian qualifier Somdev Devvarman and Argentina's Leonardo Mayer crushed French qualifier Josselin Ouanna 6-2 6-3.

In other matches, Latvian Ernests Gulbis brushed aside Lu Yen-hsun of Taiwan 7-5 6-2 and Cypriot Marcos Baghdatis, the 2006 Australian Open runner-up, beat Canada's Frank Dancevic 7-6 6-3.

"I am happy to win my first match here and I feel like I'm playing much better," said former world number eight Baghdatis, whose ranking has plunged to 146th.

"I've been practising really hard and I am trying to get back to my old form."

Top-seeded German Tommy Haas, tournament champion in 2004 and 2006, will launch his bid for a third title at the hardcourt event when he takes on American wildcard Jesse Levine in the second round on Wednesday.

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