- Associated Press - Wednesday, August 4, 2010

WASHINGTON (AP) - Janko Tipsarevic took advantage of Sam Querrey’s mistakes and found his serve late to upset the sixth-seeded American 7-6 (3), 6-3 on Wednesday in the second round of the Legg Mason Tennis Classic.

Querrey double-faulted on break point to give Tipsarevic a 5-3 lead in the second set. Querrey’s third double fault of the match proved costly, as Tipsarevic served three straight aces in the next game to seal the match.

Tipsarevic had an first-serve percentage of only 39 in the first set but found his rhythm in the second, raising his percentage to 82. Tipsarevic totaled with 16 aces.

No. 9-seed Ernests Gulbis retired from his match due to heat after falling behind Illya Marchenko 6-1, 1-0 in the other early match Wednesday.