Kim Clijsters erased an early first-set deficit and put her hopes of defending her U.S. Open title back on track with a 6-3, 6-0 win against Petra Kvitova on Friday that secured the Belgian a spot in the fourth round.  With a win, the second seed Clijsters also extended her winning streak of at Flushing Meadows to 17 matches.

Clijsters said she was not worried when she fell down 3-0 in the first set. "I was just focused on every point. My attitude never really changed whether I was up or down and when you’re not playing your best tennis that’s how you have to play … Until the set is over you can always come back and win, and that’s what I tried to do."

Women’s fifth seed Samantha Stosur and 11th seed Elena Dementieva advanced in straight sets to face each other in the fourth round.

A reporter asked her if she felt last year's title was tarnished because Serena Williams lost on a foot fault and how the absence of Williams at this year's Open has affected the field.

"My tournaments are not based on what Serena does," Clijsters said. "I have to focus on what I do best and that’s playing good tennis. Whether she’s here or not I have to play my best tennis."

Stosur, the runner-up at the French Open in June, topped Italy’s Sara Errani 6-2, 6-3 on the Louis Armstrong Stadium court, the No. 2 stadium, at the National Tennis Center in New York.

Stosur forced the action, making 37 winners and 29 unforced errors, compared with 10 winners and 12 unforced errors by Errani.

"I moved really well," Stosur  said. "It's always something I work on, and I guess it was something I paid a lot more attention to the couple of weeks I wasn't able to play. All I could do is footwork stuff. I think I'm seeing the benefits of that now."

Dementieva beat 24th seed Daniela Hantuchova of Slovakia 7-5, 6-2 to open play today on the Arthur Ashe Stadium court.

Dementieva, the 2004 U.S. Open runner-up, was 6-for-6 on break points and was broken three times.

Dementieva said she is looking forward to a good match with Stosur.

"It's always good to have positive experience against a player, but I think it's going to be a different match," Dementieva said. "We haven't played for a long time, and Samantha really improved her game a lot. She's playing very well this season -- a finalist in the French Open. She's a very solid player with a huge serve, and, yeah, I expect a tough match against her."

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