Janko Tipsarevic gained a measure of revenge for his loss to Sam Querrey last week by shocking the hard-serving American 7-6, 6-3 under sweltering conditions on Wednesday at the Washington Classic.
The unseeded Serb lost only six points on his serve during the second-round match against Querrey despite successfully landing only 56 percent of his first serves.
Tipsarevic squandered a second-set match point to Querrey in the semi-finals of the Los Angeles Open last week. The American ultimately went on to claim his fourth title of 2010.
"I was focused from start to finish," Tipsarevic told reporters after Wednesday's 78-minute match.
"I could see Sam was a little bit tired from the LA week. I'm so happy in these conditions I managed to close it out in two sets," he added.
In other matches at the hardcourt event where temperatures reached into the low 90s (32 Celsius), Ukrainian Illya Marchenko was leading Ernests Gulbis 6-1, 1-0 when the ninth-seeded Latvian wilted in the steamy conditions and retired.
Australia's Lleyton Hewitt, who won the Washington tournament in 2004, suffered an injury to his right calf during his match against Colombian Alejandro Falla and retired. The 11th seed was down 7-5, 3-2 when he quit.
There were no service breaks in the opening set of the Querrey match and in the first point of the tiebreak the 22-year-old American rifled a 137 mph (220kph) second serve wide to gift-wrap a mini-break to Tipsarevic.
The 26-year-old Tipsarevic, who blasted 16 aces, won the tiebreak 7-3 and said watching Querrey attempt big shots on his second serve during the first set gave him a boost.
"At one point I was getting aggravated because two or three times we played a very tough game and its 30-30 and he has a second serve," said the 41st-ranked Tipsarevic.
"On one side it was getting me nervous but on the other it gave me mental strength, saying to myself, 'he's getting tired. Just hang in there.' I managed to stay disciplined and (the double fault) finally came."
Querrey, seeded sixth in Washington, offered no excuses for the loss.
"Janko played great out there. He had a big serve, ripped the ball from both sides. I had a tough time staying in any of his service games," he said.
