Roddick falls in Carolina

Winston-Salem, NC (Sports Network) - Fifth seed Andy Roddick suffered a third-round upset loss Wednesday at the $550,000 Winston-Salem Open, a final U.S. Open tune-up.

Capable Belgian Steve Darcis drove out the American slugger Roddick in a pair of tiebreaks, 7-6 (8-6), 7-6 (7-3), on the hardcourts at Wake Forest University.

The former world No. 1 and former U.S. Open champion Roddick lost early at last week's Masters event in Cincinnati, where he was slowed by back problems. He's now dropped three of his last four matches after winning five straight, including a hardcourt title in Atlanta.

Meanwhile, fourth-seeded Alexandr Dolgopolov of Ukraine moved into the quarterfinals with a 6-3, 6-4 decision against 14th-seeded Argentine David Nalbandian.

Seventh-seeded American Sam Querrey, who currently leads the U.S. Open Series standings, continued his fine summer with a 6-3, 6-4 victory over ninth-seeded Spaniard Feliciano Lopez on Day 4. Querrey will meet Dolgopolov in the round of eight on Thursday.

The 2012 Winston-Salem champion will collect $73,930.