Roddick, who will face seventh-seed Xavier Malisse of Belgium in the quarterfinals, is aiming for his 20th career tournament title on hardcourts and third this year.

Malisse defeated Ukraine's Illya Marchenko 6-3, 6-3, while third-seeded Lleyton Hewitt lost a late match 6-4, 6-2 to Slovakia's Lukas Lacko.

Roddick improved his ATP tour-leading match record to 27-4 on hardcourts.

"The first game of the third, I was down a couple of break points," Roddick said. "If he breaks the first game of the third, I think it's a long way back because he started serving a little bit better in the second set. That was probably the pivotal moment in the match." Former top-ranked Hewitt blamed an injury, which he refused to disclose, with keeping him from playing at full capacity. He acknowledged, however, that the injury occurred before he arrived in Atlanta.

"On Sunday, I didn't think I'd be able to compete here," Hewitt said. "For me, it was a good effort by the medical staff to be able to get me close to being 100 percent here." Lacko could tell something seemed wrong with Hewitt, who underwent hip surgery in January and missed much of 2008 with a hip injury.

"Obviously, he's got some problems," Lacko said. "He was fighting through the first set. I played good ending to the first set and after breaking the second, he seemed like ... he had some minor problems. I mean he needed a couple of extra steps on his strokes." Sixth-seeded Mardy Fish withdrew from doubles Thursday after twisting an ankle late in a second-round singles victory the night before over Robby Ginepri.

Fish, who needs to rest before his quarterfinals match, was supposed to partner Roddick in the postponed doubles match.

In quarterfinal singles, Lacko will play Russia's Kevin Anderson, a 7-5, 6-3 second-round winner over Donald Young.

After No. 2 seed John Isner faces Michael Russell, Roddick-Malisse and Fish-Taylor Dent are the night matches.


In Bad Gastein, Austria, Timea Bacsinszky of Switzerland became the only seeded player to reach the semifinals of the Gastein Ladies on Friday.

The second-seeded Bacsinszky eased past Sandra Zahlavova of Czech Republic 6-0, 6-4 and plays Austria's Yvonne Meusburger for a place in Sunday's final. Meusburger defeated No. 8 Anastasija Sevastova 7-5, 6-4.

Earlier Friday, Alize Cornet of France and Julia Goerges of Germany advanced to the semifinals.

The 52nd-ranked Bacsinszky took the first seven games against Zahlavova, who won only three points on serve in the opening set.

The Czech managed an early break in the second, but dropped serve twice as Bacsinszky advanced to her first semifinal of the season.

Bacsinszky had won the only previous meeting against Zahlavova by the same score in Rome last May.

Meusburger, who reached the final against eventual champion Francesca Schiavone in 2007, saved five of seven break points against Sevastova.

Cornet defeated Austrian wild card Patricia Mayr 6-2, 6-7 (5), 6-2. The 81st-ranked Cornet, who eliminated top-seeded defending champion Andrea Petkovic on Thursday, broke Mayr nine times to qualify for her second semifinal of the season.

Goerges beat Russia's Anastasia Pivovarova 6-4, 6-7 (5), 6-4. The German, ranked 65th, was broken while for serving for the match at 6-5 in the second set but had three breaks in the decider to close out the match.
 

In Hamburg, Germanuy, third-seeded Jurgen Melzer of Austria beat Potito Starace of Italy 6-4, 6-1 to reach the semifinals of the German Open.

Melzer will meet another Italian in the semifinals of the clay-court tournament, Andreas Seppi, who upset seventh-seeded Thomaz Bellucci of Brazil 7-6 (0), 5-7, 7-5.

Melzer was a semifinalist at the French Open and is the highest seeded player left in the field. He was a semifinalist in Hamburg in 2004, while Seppi reached the last four in 2008.