Serena and Venus Williams advance at U.S. Open

Serena Williams took only 53 minutes and committed only nine unforced errors in her 6-1, 6-1 second-round victory over 51st-ranked Melinda Czink of Hungary.

It was an emphatic win and it prompted Serena to do a little happy dance when it was over. That was in contrast to a second-round match earlier in the day when Venus Williams played with her left knee heavily taped.

That didn’t stop third-seeded Venus from dispatching 124th-ranked Bethanie Mattek-Sands, 6-4, 6-2, and moving closer to an anticipated fourth-round encounter with 2005 Open champion Kim Clijsters.

Clijsters, who hasn’t played here since ’05 and who has been back on the circuit for only a month after ending a two-year retirement, upset 14th-seeded Marion Bartoli, 5-7, 6-1, 6-2.

While Williams refused to talk about her knee, Clijsters said she’d be interested to see how that knee holds up. “I think what we don’t know is how her knee is going to react after a couple of matches,” Clijsters said.

Williams neither complained about pain nor offered explanations on why the knee hurts, except to say, “Wear and tear does put a lot on your body. It’s September now. I started, literally, in December. So I guess it’s not a huge surprise that at this time of the year things start to be a little sore and start to hurt.”

The men’s matches continued to be mostly uneventful. Five-time defending champion and top-seeded Roger Federer beat 28-year-old Simon Greul of Germany, 6-3, 7-5, 7-5. He finished off the match with an ace.

And Rafael Nadal got out of his first-round match so easily it was hard to tell whether his sore knees were a problem. He beat Richard Gasquet of France, 6-2, 6-2, 6-3.

Other notable winners: 13th-seeded Gael Monfils, seventh-seeded Vera Zvonareva and L.A. Women’s Tennis Championships winner Flavia Pennetta, who blanked Sania Mirza, 6-0, 6-0.

Stat of the day

In his 5-7, 6-2, 6-4, 6-0 loss to Robby Ginepri, Romania’s Andrei Pavel won zero points off his second serve in the final set.

Upset of the day

Vania King, a 20-year-old from Long Beach who is ranked 114th in the world and needed a wild-card invitation into the draw, knocked out 15th-seeded Samantha Stosur of Australia, 6-4, 7-5.

Quote of the day

Marat Safin, a former No. 1-ranked player who is heading into retirement now that he lost here, is the big brother of women’s top-ranked Dinara Safina, who is often questioned about being No. 1 without a single major tournament win. “Who cares?” he said. “I mean, she’s No. 1 in the world. I have to protect my sister. The poor girl, she’s trying her best.”

Today’s featured matches

At Arthur Ashe Stadium, beginning at 8 a.m. PDT, fourth-seeded Elena Dementieva goes against 17-year-old American Melanie Oudin, followed by fifth-seeded Jelena Jankovic and Yaroslava Shvedova and finally 21st-seeded James Blake versus Olivier Rochus. The night session at 4 p.m. starts with another 17-year-old American, Christina McHale, who is ranked 381st, against 29th-seeded Maria Sharapova, followed by night owl Andy Roddick (he was in the second night match Monday) against Marc Gicquel.

Out and about around the grounds: Unsteady but top-seeded Safina is on at 8 a.m. against Kristina Barrois and is followed by an all-American match between 22nd-seeded Sam Querrey and Kevin Kim. The fourth match at Louis Armstrong Stadium has fourth-seeded Novak Djokovic against Newport Beach resident and qualifier Carsten Ball, who started his good summer with a runner-up finish to Querrey at the L.A. Open. And at the Grandstand, not before 11 a.m., the Williams sisters are scheduled to play Julia Goerges of Germany and Arantxa Parra Santonja of Spain, followed by the top-seeded doubles team of Bob and Mike Bryan against Argentines Jose Acasuso and Martin Vassallo Arguello.

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diane.pucin@latimes.com

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