Updated

Former world No. 1 Victoria Azarenka was an easy second-round winner, while American Bethanie Mattek-Sands stunned former champion Li Na in Thursday's action at a rain-plagued French Open.

The third-seeded Azarenka handled young German Annika Beck 6-4, 6-3 on Court Lenglen. The shrieking Belarusian star is the reigning Australian Open champion and was last year's U.S. Open runner-up.

Up next for Azarenka will be French crowd favorite Alize Cornet.

Meanwhile, the oft-injured Minnesota native Mattek-Sands recorded the biggest win of her career by dousing the sixth-seeded Li in 5-7, 6-3, 6-2 fashion in 2 hours, 16 minutes on Court 1 at Stade Roland Garros.

The 67th-ranked Mattek-Sands won seven straight games at one point to grab a commanding 5-0 lead in the final set on yet another wet, chilly day in Paris.

"She's a champion, and I had to play some of my best tennis ever to beat her," Mattek-Sands said. "I'm really proud of myself that I was able to close out the match the way I did."

The 31-year-old Li refused to make any excuses after the loss.

"I know for sure that I don't normally lose seven games in a row," she said. "It was very tough conditions, coming back to the court three times. But for both players it was the same.

"I should find out what happened and I'll talk to myself, my team to see what happened."

The 28-year-old Mattek-Sands posted the fourth top-10 win of her career and her second of 2013. She upset 2012 French Open runner-up Sara Errani on some red clay in Stuttgart last month.

Li was this year's Aussie Open runner-up to Azarenka and captured the lone Grand Slam title of her career at the 2011 French Open.

Second-seeded and defending champion Maria Sharapova was leading promising Canadian Eugenie Bouchard 6-2, 4-2 when play was halted on Day 5.

Rain interrupted the tennis several times on Thursday, forcing the suspension or postponement of five women's singles matches.

The former No. 1 Sharapova completed a career Grand Slam by titling here a year ago, including a victory over Errani in the final.

Seventh-seeded former Wimbledon champ Petra Kvitova improved to 7-1 in her last two trips to the French Open with a 6-4, 6-3 victory over last week's Brussels runner-up Peng Shuai of China, while ninth-seeded former Roland Garros finalist Sam Stosur reached the third round with a 6-4, 6-3 handling of France's Kristina Mladenovic. The former U.S. Open champion Stosur was the runner-up here three years ago.

Sloane Stephens, seeded 17th at this fortnight, improved to 7-1 in Grand Slam action this year with a workmanlike 6-1, 6-3 spanking of fellow American Vania King, while 18th-seeded former world No. 1 Jelena Jankovic of Serbia drubbed Spaniard Garbine Muguruza 6-3, 6-0 to reach the round of 32.

"I know that when I'm healthy and free of injuries I'm still capable of playing great tennis," said Jankovic, a former U.S. Open runner-up.

She will meet Stosur on Saturday.

In other action involving seeds, New Zealand's Marina Erakovic upended No. 16 Dominika Cibulkova of the Slovak Republic 6-2, 2-6, 6-4, Argentine Paula Ormaechea took out No. 27 Yaroslava Shvedova of Kazakhstan 6-4, 7-6 (8-6), and a No. 31 Cornet dispensed Spaniard Silvia Soler-Espinosa 6-1, 6-3. Cornet is fresh off her clay-court title in Strasbourg, France. Erakovic will encounter Stephens, while Ormaechea will face Mattek-Sands in an unlikely third-rounder on Saturday.

Also, American Jamie Hampton beat Slovak Anna Schmiedlova 7-5, 6-2 and Chinese Zheng Jie leveled American Melanie Oudin 6-3, 6-1. The 23-year-old Hampton is rewarded with a third-rounder against the formidable Kvitova.

Twelfth-seeded Russian Maria Kirilenko was tied with Aussie Ashleigh Barty 3-3 in the opening set and last week's Brussels champion Kaia Kanepi of Estonia was ahead of Swiss Stefanie Voegele 6-5 in the first set when play was called for the day.

The third round will get underway Friday, including matches for world No. 1 Serena Williams, fourth-seeded Wimbledon runner-up Agnieszka Radwanska and a fifth-seeded Errani. The 15-time Grand Slam singles titlist Williams will take on 26th-seeded Romanian Sorana Cirstea, while Radwanska will meet German Dinah Pfizenmaier and Errani will be opposed by 32nd-seeded German Sabine Lisicki.

The red-hot 31-year-old Williams, the 2002 French Open champion, is currently riding a 26-match winning streak and is 69-3 overall since suffering a shocking first-round loss at the hands of French journeywoman Virginie Razzano at last year's French Open.

Williams and her older sister Venus were forced to pull out of the doubles draw, as Venus is nursing a sore back. The mighty sisters were seeded 12th at this fortnight and are two-time French Open champions (1999, 2010).