updated 3:44 p.m. ET Sept. 2, 2009

NEW YORK - Serena Williams has joined her sister in the U.S. Open’s third round with a dominating victory.

The No. 2-seeded Williams was pretty close to perfect in beating 51st-ranked Melinda Czink of Hungary 6-1, 6-1 in less than an hour Wednesday night.

Williams is seeking her fourth U.S. Open championship and 12th Grand Slam singles title overall. The American is trying to become the first woman to win consecutive titles at Flushing Meadows since her older sister Venus in 2000-01.

The siblings could play each other in the semifinals. Venus Williams moved on easily.

Her left knee heavily wrapped, the third-seeded Williams defeated Bethanie Mattek-Sands 6-4, 6-2, in a much easier match than she had two nights before when she fell behind a set before rallying against Vera Dushevina.

She hurt the knee in the opener, but if she was still in pain in the second round, her opponent couldn’t tell.

“She was moving like a cat,” Mattek-Sands said.

Two-time major champion Amelie Mauresmo fell 6-4, 6-0 to Aleksandra Wozniak. Mauresmo recently turned 30 and is also thinking about retirement, though she won’t commit to a decision.

“The thing I don’t want to do is make the decision to stop and then after two, six, eight months think, it was not quite the time yet,” Mauresmo said. “Because then it’s too hard, I would say, probably to make a comeback as Kim is making now, given the age.”

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Other seeded winners from early action Wednesday were No. 7 Vera Zvonareva, No. 18 Li Na and No. 31 Elena Vesnina. No. 10 Flavia Pennetta also won 6-0, 6-0 over Sania Mirza — the first double-bagel of this year’s tournament.

Kim Clijsters was away for two years, having ended her retirement in August, and she continues to play as if she never left. Unseeded and unranked and playing at the U.S. Open for the first time since winning the 2005 title, the 26-year-old Belgian reached the third round by knocking off No. 14-seeded Marion Bartoli 5-7, 6-1, 6-2.

Others sent home included No. 15 Samantha Stosur, a French Open semifinalist, who was beaten by Vania King of Long Beach, Calif., 7-5, 6-4; two-time major champion Amelie Mauresmo, who lost to Aleksandra Wozniak of Canada; No. 12 Agnieszka Radwanska and No. 20 Anabel Medina Garrigues.

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