(CNN) -- World No. 5 Andy Roddick has made a triumphant return to tennis action following the hip injury he suffered in his epic Wimbledon final defeat to Roger Federer last month.
Andy Roddick will face rising American star Sam Querrey in the last eight in Washington.
The American opened his bid for a fourth Legg Mason Classic title in Washington with a crushing 6-3 6-2 win over unseeded German Benjamin Becker on Wednesday night.
The top seed, who was handed a first-round bye, will next play compatriot Sam Querrey in the quarterfinals of the hardcourt event, which is part of the build-up to next month's U.S. Open in New York.
"I was eager to get back out there and I'm glad to be back in the swing of it. I'm not worried about my fitness at all. I felt okay and I'd certainly like to play some more matches this week," Roddick told the ATP Tour's Web site.
The 26-year-old will seek to become the fourth active player to reach 500 career wins when he faces 16th seed Querrey, and just the 36th since the Open Era began.
Australia's Lleyton Hewitt, who is third in that list behind Carlos Moya and the top-ranked Federer, joined his Wimbledon conqueror Roddick in the last eight with a 6-3 2-6 6-2 victory against 15th seed Dudi Sela of Israel.
Hewitt, who is also in recovery from a hip problem that ruined most of last season, will next play defending champion and second seed Juan Martin del Potro of Argentina.
Hewitt joined another former world No. 1 in progressing as Juan Carlos Ferrero upset seventh-seeded Spanish Davis Cup teammate Tommy Robredo 6-3 6-2 to set up a clash with German 10th seed Tommy Haas.
It was a tough day for the top-ranked players, with seven seeds knocked out of the tournament.
American John Isner served up 20 aces as he stunned French third seed Jo-Wilfried Tsonga 4-6 7-6 (7-2) 7-6 (7-4) despite a brief break for rain.
He will next face 31-year-old French qualifier Sebastien De Chaunac, who later upset No. 14 seed Dmitry Tursunov of Russia 3-6 7-6 (7-3) 7-5.
Fifth seed Robin Soderling crushed Tursunov's compatriot Mikhail Youzhny 6-3 6-1 and will next play unseeded Frenchman Marc Gicquel, who went through when 12th seed Viktor Troicki of Serbia retired with an injury while 3-0 down in the first set.
American ninth seed Mardy Fish also exited after being hampered by the abdominal problem which forced him to forfeit in the L.A. quarterfinals.
He was beaten 1-6 6-4 6-1 by unseeded German Philipp Petzschner, who will take on Czech eighth seed Tomas Berdych in the last eight.
Querrey, who beat unseeded Russian Igor Kunitsyn 6-3 6-4, is hoping to build on his L.A. Open title last weekend.
He became the first American since Roddick to reach three consecutive ATP Tour finals, and has launched himself up the world rankings to 26th.
"I had a lot of break-point chances tonight which is not something I expect to happen against Andy," Querrey told the ATP Web site.
"If you get one break-point you are lucky. If a chance comes you can't be careless, but you can't just push a return in. You've got to take a chance."
Roddick, who improved his record to 40-9 this season, has won their last two encounters.
"We do a lot of the same things. He plays big and he's in form," Roddick said.
"He also has a full month of matches behind him going in. It'll probably come down to a few points here and there because we should both be able to hold serve."