Andy Roddick rolled into the semi-finals of the Washington Open but second seed Tommy Haas and number three Marat Safin were ousted on Friday from the US Open tune-up.
Roddick fired 16 aces to defeat South Korea's Lee Hyung-taik for the 10th time in 11 career meetings, 7-6, 6-2.
"That was by far the best I've hit the ball this tournament," said Roddick.
"He gets into a groove sometimes and you just have to stay the course and wait for the opportunities. I did a good job of that.
"I felt like I was in control of my service games and even when I was down I felt like I controlled the pace of the match."
In Saturday's semis, Roddick will face Ivo Karlovic, the hard-serving Croatian who escaped with a 4-6, 6-3, 7-6 quarter-final victory over Paul Capdeville of Chile.
Haas went out to 416th-ranked John Isner, a 6 ft 9 ins American playing in just his second ATP event. Isner blasted 30 aces to subdue the German 6-4, 6-7, 7-6 in a two-hour, 27-minute match on a steamy day in Washington.
"He's got a big game," admitted Haas. "His serve is a huge, huge weapon. He's got to be happy about his third-set tiebreakers this week.
"Confidence does a lot for you. I'm sure he's feeling pretty good right now."
Next up for Isner will be Frenchman Gael Monfils, the ninth seed who recorded 14 aces to beat Safin 6-3, 7-5.
Isner, a crowd favourite in underdog-loving Washington, won his third-set tiebreak 7-5 when Haas could not control a blistering serve to his backhand.
A finalist in the 2007 NCAA singles tournament with the University of Georgia, Isner has won all four of his matches this week by clinching third-set tiebreaks.
He opened with a victory over Britain's Tim Henman before toppling Benjamin Becker of Germany and American qualifier Wayne Odesnik.
"Tommy's a great player, having won so many tournaments after playing so well for so long," said Isner, who was granted a wild card into the tournament when Fernando Gonzalez withdrew with a sore back.
"He's just so steady out there with his serve. But my serve kept me in the match. This is a dream come true. I can't believe I won in that fashion once again."
Haas, ranked 12th in the world, was playing in his first tournament since withdrawing prior to his fourth-round match at Wimbledon with a torn stomach muscle.