MEMPHIS, Tenn. -- Top-seeded Andy Roddick moved into the quarterfinals of the Regions Morgan Keegan Championships with a 7-6 (2), 6-4 victory over Yen-Hsun Lu of Taiwan on Thursday night.
Roddick, pushed to three challenging sets in a first-round win over James Blake, advanced to the quarterfinals in Memphis for the ninth straight year. Roddick, the world's seventh-ranked player, is the tournament's defending champion.
Roddick relied on 10 aces and a key break of serve to beat Lu, who at No. 114, was one of the lowest-ranked players in the 32-man field.
After failing to break Lu on seven earlier opportunities, Roddick converted on the eighth by double-fault. The mistake by Lu gave Roddick a 5-4 lead in the second set. He served out for the match, winning on an ace.
"It was good. But if I want to go further in this tournament I've got to do better on break points," Roddick said. "That was really ordinary. The one I ended up getting was because he doubled.
"I'm doing a good job of getting (break points). I feel like I'm in every (opponent's) service game, but I can't miss second-serve returns at 15-30 or 30-all. I'm very close to playing really well. It's just a matter of tightening things up to make that happen."
Other seeds advancing to the quarterfinals were No. 5 Tomas Berdych and No. 8 Sam Querrey. Berdych defeated unseeded American Michael Russell, 3-6, 6-3, 6-2 and Querrey beat Argentina's Leonardo Mayer, 6-4, 6-0.
In the women's portion of the event -- the Cellular South Cup -- top-seeded Maria Sharapova continued her dominating march with a 6-2, 7-5 victory against Elena Baltacha of Great Britain to reach the semifinals.
Sharapova, the world's 16th-ranked player, has not dropped a set and lost only 11 games in three matches in her first tournament since losing in the first round of the Australian Open last month.
Second-seeded Melanie Oudin, the 18-year-old American who stunned Sharapova at last year's U.S. Open, was upset in the quarterfinals by qualifier and 2006 Memphis champion Sofia Arvidsson of Sweden. Arvidsson, who barely made it to Memphis in time to compete in the qualifying, won 6-1, 6-3.
Arvidsson, ranked 139th, had to rush from a $100,000 total prize money minor tour event in Midland, Mich., to participate in the qualifying, which began Friday.
"I didn't arrive until an hour and a half before my qualifying," she said. "I almost didn't make it into the tournament. I've been lucky this week. I've been fighting through my matches. It's been unbelievable."