Petra Kvitova took 54 minutes to reach the quarterfinals and keep her summer winning streak alive.
WTA Staff

CINCINNATI, OH, USA - Six of the WTA's brightest stars moved into the quarterfinals of the Western & Southern Open on Thursday, with two third round matches pushed to Friday's schedule after some evening rain.

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No.1 seed Agnieszka Radwanska probably had the toughest day at the office, needing an hour and 57 minutes - nearly half of which was made up of a grueling third set - to defeat American wildcard Sloane Stephens, 61 46 64.

It wasn't an easy day for No.2 seed Serena Williams, either, as she was down a break twice in the first set and trailed 3-0 in the second before battling back to make it past the younger Radwanska, Urszula Radwanska, 64 63.

The elder Radwanska talked about her younger sister's match: "They've played so many times the last couple of weeks - I think the third time. My sister's like, 'Why do I always have to play Serena? The draw is so big, and it's always Serena.' But yeah, there's really no way to change things like that.

"Ula was playing really great tennis here. It was her fifth match of the week. Sometimes the fifth match is the final, so for sure she wasn't that fresh. But losing against Serena can even be a good experience. I don't know what she's going to say about the match after, but I think she really played well."

Williams was asked to compare and contrast the Radwanska sisters. "I think they're both great players, and great sisters. I absolutely love seeing another pair of sisters doing so well on the tour," Williams said. "Urszula has worked really hard, and me being a younger sister and Urszula being a younger sister too, I'm always looking for her to do well and I hope she does really well.

"Her game is great. What's best about her game is she's like her sister - she doesn't do anything badly. Those are always tough opponents to play."

Speaking of sister acts, Venus Williams had the most convincing win of the three, maybe even the most convincing win of the day, winning seven games in a row from 5-3 in the first set to rout No.7 seed Sara Errani, 63 60.

"I played her at the Olympics, too. I was familiar with her game because I just played her a few weeks ago. I think that helped me a lot," Williams said. "I've beaten two seeds here now, players who are having exceptional years and are confident. For me to be in this tournament and getting wins over both of those players feels really good. I want to continue this in my next match tomorrow."

Williams is now through to her fourth quarterfinal since coming back from her seven-month illness lay-off, and they've all come at Premier events - Miami, Charleston, Rome and now Cincinnati. The seven-time Grand Slam champion and former World No.1 is feeling her former momentum coming back.

"Before all my injuries and illnesses I was No.2 in the world and Serena was No.1, and we were No.1 in doubles. We were literally on top of the world until a lot of things came crashing down on us," she said. "I'd like to work my way back. Of course that's a dream for me. I dream of those things. That's why I'm here, because I feel like I still have it. It's one match at a time, pretty much."

Other winners during the day session were No.3 seed Sam Stosur, who beat Ekaterina Makarova, 61 63; No.4 seed Petra Kvitova, who beat Peng Shuai, 62 62; and No.5 seed Angelique Kerber, who rallied from 4-1 down in the second set tie-break to beat Czech qualifier Andrea Hlavackova, 64 76(5).

Two more matches were scheduled for later in the evening but rained out - No.6 seed Caroline Wozniacki had lost the first set against No.17 seed Anastasia Pavlyuchenkova, 6-4, when play was stopped; No.9 seed Li Na never took the court against qualifier Johanna Larsson. Those will be played on Friday.