Three-time champion Kim Clijsters, playing in her final WTA event, came up a second-round loser Wednesday at the U.S. Open.

The 23rd-seeded former world No. 1 succumbed to rising 18-year-old British left-hander Laura Robson 7-6 (7-4), 7-6 (7-5) at Ashe Stadium.

"This seems like the perfect place to retire, I just wish it wasn't today," said an emotional Clijsters.

Clijsters saved two match points, trailing 5-6, 15-40 in the second set, but was unable to stave off a third in the second-set tiebreak, as the Belgian wife and mother sent one final backhand return long on Day 3.

The 29-year-old star hadn't lost at the U.S. Open since falling to Justine Henin in an all-Belgian final in 2003. She'd won her last 22 matches on the famed hardcourts in Flushing.

Clijsters, who is still in the doubles draw, was the U.S. Open champ in 2005, 2009 and 2010 and settled for a 38-6 singles record at America's Open.

The oft-injured four-time Grand Slam singles champ, who turned pro in 1997 and retired from the WTA for the first time in 2007 in order to start a family, corralled 41 career titles and also helped Belgium win its lone Fed Cup title back in 2001. Clijsters was also a four-time major runner-up.

Other big names moved on Wednesday, including world No. 1 Victoria Azarenka, defending champion Samantha Stosur, former winner Maria Sharapova and last year's Wimbledon champion Petra Kvitova.

The Belarusian star Azarenka whipped Belgian qualifier Kirsten Flipkens 6-2, 6-2 in 65 minutes at Ashe. Flipkens is a former U.S. Open girls and junior world champion who is playing doubles alongside Clijsters.

Azarenka, a former U.S. Open mixed doubles champ, has been No. 1 for most of the year after capturing her first major singles title at the Australian Open back in January.

The 23-year-old Azarenka has never advanced beyond the fourth round in Flushing.

"I don't feel like I have to prove something," said the Olympic bronze medalist, who moved on to face China's Zheng Jie.

Stosur, who shocked Serena Williams in last year's final, scored a 6-3, 6-0 win over Romanian Edina Gallovits-Hall. The seventh-seeded Australian will play No. 31 American Varvara Lepchenko in the next round.

The 2006 champion Sharapova, seeded No. 3 this year, fired six aces and had no trouble in a 6-0, 6-1 win over Spaniard Lourdes Dominguez Lino. The Russian Sharapova set up a match with Stanford All-American Mallory Burdette.

Kvitova, seeded fifth, handled France's Alize Cornet 6-4, 6-3 at Armstrong Stadium. The left-handed Czech slugger, who captured both Wimbledon and the prestigious season-ending WTA Championships last year, is the only woman to reach the quarterfinals at all three Grand Slam events so far this year.

Kvitova's third-round opponent will be France's Pauline Parmentier.

Ninth-seeded Chinese Li Na continued her recent run of fine play with a 6-4, 6-4 victory over Aussie Casey Dellacqua. The 2011 French Open champion is fresh off her big hardcourt title in Cincinnati and was a runner-up to Kvitova in Montreal earlier this month.

Li's third-round opponent will be the talented Robson.

Also, No. 11 seed Marion Bartoli of France held on to beat Switzerland's Romina Oprandi 6-2, 1-6, 7-5; 15th-seeded Czech Lucie Safarova held off Canadian Aleksandra Wozniak 6-3, 4-6, 6-2; Frenchwoman Kristina Mladenovic dismissed 17th-seeded Russian Anastasia Pavlyuchenkova 6-1, 6-2; and 19th- seeded former top-10 Russian Nadia Petrova pasted Romanian Simona Halep 6-1, 6-1.

In other action involving seeds, Parmentier knocked out No. 25 Belgian Yanina Wickmayer 7-6 (7-5), 6-3, a No. 28 Zheng drubbed Slovak Magdalena Rybarikova 6-3, 6-1, and Lepchenko whipped Aussie Anastasia Rodionova 6-2, 6-2.

Another American winner was Burdette, who surprised the capable Czech Lucie Hradecka 6-2, 6-4.

Burdette is a 21-year-old from Georgia who was this year's NCAA runner-up to Nicole Gibbs, who lost in the first round this week.

"To end up here at the U.S. Open was a huge surprise," Burdette said. "I never expected that at the beginning of the summer."

Also advancing to the third round was Luxembourg's Mandy Minella and Georgian Anna Tatishvili.