NEW YORK (AP) — The US Open lost yet another top women’s player yesterday when two-time champion Venus Williams withdrew because of illness.

Williams was supposed to play 22nd-seeded Sabine Lisicki in the second round.

The 31-year-old Williams pulled out of two hard-court tuneup tournaments this summer because of a virus. In her first match in two months, Williams beat Vesna Dolonts, 6-4, 6-3, at Flushing Meadows on Monday.

Before the news broke that the older Williams sister was out, Vera Zvonareva was already happy just to advance. In a wide-open women’s draw, that counts for a lot — and that became even more true with Williams’ exit.

The second-seeded Russian needed three ragged sets to reach the third round, beating 69th-ranked Kateryna Bondarenko, 7-5, 3-6, 6-3. With the winners of the last four major tournaments missing from the second round, players with a lot of Grand Slam experience are in short supply. Zvonareva has that, losing in the final at Wimbledon and here at Flushing Meadows in 2010.

A two-time Grand Slam runner-up on the men’s side didn’t even get started at the Open. Sixth-seeded Robin Soderling withdrew because of illness before his first-round match.

One American teen pulled a big upset on the women’s side, while another couldn’t hold onto a lead.

Christina McHale reached the third round of a Grand Slam tournament for the first time, beating eighth-seeded Marion Bartoli in straight sets.

The 19-year-old from Englewood Cliffs, NJ, won 7-6 (2), 6-2. She’s ranked a career-high 55th and beat No 1 Caroline Wozniacki in Cincinnati this month.

McHale clinched the victory in style, winning the final point on an ace. The youngest woman in the top 100, McHale was playing in her eighth major tournament.

At the French Open this year, she was up 5-0 in the third set but let it slip away and was beaten 6-7 (4), 6-2, 9-7 by Sara Errani. McHale didn’t lose any leads this time.

Bartoli, a 26-year-old Frenchwoman, was a semi-finalist at Roland Garros this year.

Madison Keys couldn’t hold onto several leads in her second-round match, eventually falling to 27th-seeded Lucie Safarova in three sets.

Juan Martin del Potro played here for the first time since winning the 2009 US Open, beating Filippo Volandri of Italy, 6-3, 6-1, 6-1. The 18th-seeded Argentine was unable to defend his title last year because of a wrist injury.

Fourth-seeded Andy Murray had a tough first set then cruised the rest of the way, beating Somdev Devvarman, 7-6 (5), 6-2, 6-3, in the first round.

Tenth-seeded Nicolas Almagro of Spain lost, 6-2, 6-4, 6-3, to 81st-ranked Julien Benneteau of France.