Seeds were toppled at the Legg Mason Classic second round on a hot and humid Wednesday in Washington, with Los Angeles champion Sam Querrey brought down by the man he beat four days ago on the way to that West Coast title.

Serb Janko Tipsarevic took his revenge for a semifinal loss in LA against the sixth-seeded American, winning in just over an hour and a quarter.

The inspired and unseeded challenger outaced the California big man 16 to 13 with a break of Querrey in the eighth game of the second set paving the way for the win.

Tipsarevic will play on Thursday against Colombian Alejandro Falla, who went through after former champion Lleyton Hewitt, seeded 11th, had to quit trailing 7-5, 3-2 after suffering an ankle injury.

Querrey opened play after the bye awarded to all 16 seeds, while Tipsarevic had opened in the first round by defeating Arnaud Clement.

“It was tough to adjust to conditions between LA and here,” said Querrey. “Janko played great, he ripped the ball. I was struggling to stay with him. I’m not discouraged, I’m still playing great.”

Argentine David Nalbandian continued his comeback as he stopped Swiss number seven Stanislas Wawrinka 6-1, 6-3. Eighth-seeded Cypriot Marcos Baghdatis needed a pair of tiebreaks to deal another loss to Argentina as he defeated Horacio Zeballos 7-6 (7-3), 7-6 (7-5).

Ukrainian Illya Marchenko made his adjustment to the draining heat, advancing to the third round when ninth-seed Ernests Gulbis quit with exhaustion trailing 6-1, 1-0 after just 36 minutes.

“I could tell there was something not right with his game,” said Marchenko after his third hard-court win over the post-Wimbledon summer. “I’m feeling very sure about my game.

“I’m improving with every match. I wasn’t bothered by the weather, as I got used to it a fortnight ago in Atlanta, where it was the same.

Querrey went down without a fight after winning his second consecutive LA trophy with a defeat of world number four Andy Murray.

The American got caught out in the opening set tiebreaker and could not get on top of Tipsarevic, against whom he had to save a match point in their LA semifinal last Saturday.

Tipsarevic never faced a break point while breaking Querrey only once.

Swiss Marco Chiudinelli put out another seed as number 10 Radek Stepanek had no firepower in a 6-1, 6-3 loss.

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