WASHINGTON: US top seed Andy Roddick captured the 500th match victory of his career on Thursday, defeating countryman Sam Querrey 7-6 (7/4), 6-4 to reach the quarter-finals of the ATP Washington Classic.

Roddick became the 36th Open-Era player to reach 500 match triumphs and the fourth active player at the mark, the ninth-year professional joining Federer with 657, Spain's Carlos Moya on 573 and Australian Lleyton Hewitt with 511.

"It's a pretty small number who have gotten there, an elite group," Roddick said. "Moreso, I got there with enough time to add to it significantly. It's just a nice validation of the consistency I've been able to have in my career."

Fifth-ranked Roddick, who turns 27 later this month, won his only Grand Slam title at the 2003 US Open. He seeks a 29th career crown this week and fourth Washington title to go with the cake he received for his 500th match victory.

"That's kind of a milestone in tennis," Roddick said. "It's a very humbling experience. Who knows? We might try for 500 more."

Roddick, in his first event since losing a five-set thriller to Federer in last month's Wimbledon final, will play big-serving Ivo Karlovic for a semi-final spot in the 1.4 million-dollar hardcourt event.

Karlovic ended the dream run of India qualifier Somdev Devvarman 7-5, 6-1. The two-time US college champion who ousted Croatian sixth seed Marin Cilic in the second round had beaten Karlovic in a January run to the final at Chennai.

Roddick is 4-1 lifetime against Karlovic, having never surrendered a service break to the Croatian in 12 sets, losing sets only in tie-breakers. The lanky Karlovic leads the ATP in aces this season with Roddick second.

"I've never lost a set to him. Now I've probably just jinxed myself," said Roddick. "Against him, a lot of it is out of your control."

Roddick, who fired only three aces, won four of the last five points in the tie-break and broke Querrey in the third game of the second set, then saved two break points in the final game, winning when Querrey sent a backhand long.

"I served badly," Roddick said. "It's almost gratifying. That's a match I could have lost in the last couple years."

Querrey, ranked 26th, has been sizzling the past month, reaching the finals at Newport and Indianapolis and winning last week's title at Los Angeles.

"I thought tonight would offer a truer sense of where my game is," Roddick said.

Karlovic fired 14 aces, 11 in the first set, and connected on 63 percent of his first serves to beat Devvarman, who hit 70 percent of his first serves but was broken in the last game of the first set and twice in the second set.

"It's really hard to break his serve when he is serving that well," said Devvarman. "I was doing well and then he got the break. Momentum went his way after that."

Devvarman will jump about 10 spots in the rankings to 143rd after reaching a career-high of 127 last month.

"I feel like the summer started on the right note," he said.

Former world number ones Hewitt and Juan Carlos Ferrero of Spain both lost.

Defending champion and second seed Juan Martin Del Potro of Argentina ousted Hewitt 4-6, 6-3, 7-6 (7/2) to avenge a straight-set loss to the 42nd-ranked Aussie in the second round this year at Wimbledon.

Tommy Haas blasted 19 aces to defeat Ferrero 7-5, 2-6, 6-1. The 31-year-old German improved to 18-4 since May in a run that includes a title at Halle and a Wimbledon semi-final run before losing to Federer.