Australian Open: Defending champ Azarenka holds on

Melbourne, Australia • Defending champion Victoria Azarenka struggled to hold off injured American Jamie Hampton 6-4, 4-6, 6-2 on Saturday before advancing to the fourth round of the Australian Open.

Hampton, who needed a medical timeout for a lower back problem before she served out the second set and winced in pain, frequently on the verge of tears, throughout the third, still managed to hit 41 winners to keep top-ranked Azarenka under pressure.

Azarenka appeared frustrated at times, but overcame an early break and fended off triple break point in the seventh game of the deciding set before clinching the match in 2 hours, 9 minutes.

She didn't help herself with six double faults and 28 unforced errors, but was often pushed to the limit by a rival who was swinging hard at every opportunity.

"She played incredible, went for every single shot. I felt it was touching every single line," Azarenka said. "She took a medical timeout, but she rips winners all over the place and I was like, 'Can I have a back problem?' I'm feeling great, but I'm missing every shot."

Even with the pain of two herniated disks, the 23-year-old Hampton, from Auburn, Ala., went down swinging — making 47 unforced errors to go with the winners that caught Azarenka off guard and had her asking what she could do to counter them.

On Friday night, Maria Sharapova celebrated with extra exuberance after her 6-1, 6-3 win over Venus Williams, her first victory over the seven-time major winner in a Grand Slam.

"I was just really pumped," she said. "Why shouldn't I be?"

After back-to-back 6-0, 6-0 wins in the first two rounds — the first time that happened at major since 1985 — Sharapova has conceded the fewest number of games en route to the fourth round at the Australian Open since Steffi Graf did so 24 years ago.

Top-ranked Novak Djokovic took another step closer to a third consecutive Australian title, defeating Radek Stepanek 6-4, 6-3, 7-5 in the third round.

His victory came on the same day Lance Armstrong admitted during a television interview with Oprah Winfrey that he used banned drugs to win his seven Tour de France titles. Djokovic, a lifetime cycling fan, said at his post-match news conference that it was "a disgrace for the sport to have an athlete like this." —

Highlights

O Defending women's champion Victoria Azarenka fends off Jamie Hampton, 6-4, 4-6, 6-2.

• Maria Sharapova earns her first win over Venus Williams, 6-1, 6-3. —

On TV

O Saturday, 5 a.m. (tape), 7 p.m., 1 a.m. ESPN2