PARIS -- Bethanie Mattek-Sands skipped backward across the clay, her wagging tongue framed by a smile as she savored yet another surprising victory for American tennis at the French Open.
Rejuvenated by a rain delay, Mattek-Sands rallied past 2011 champion Li Na 5-7, 6-3, 6-2 Thursday in the second round at Roland Garros.
Following the second interruption of the match, Mattek-Sands swept seven consecutive games to take a 5-0 lead in the final set. She served out the victory with the sun shining as rain fell.
"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."
Mattek-Sands was one of five U.S. women to reach the third round. Joining her Thursday were No. 54-ranked Jamie Hampton, who matched her best Grand Slam showing by beating Anna Karolina Schmiedlova 7-5, 6-2, and No. 17 Sloane Stephens, who defeated fellow American Vania King 6-1, 6-3.
"Other than Serena, we're all a work in progress. A couple years ago, we were not even here. And so we've definitely taken a step forward and we're still progressing and still trying to make that push," said Hampton. "Whenever you have a big group like that, there are going to be a few that are going to rise."
Up next for the 23-year-old Hampton is No. 7 Petra Kvitova, the 2011 Wimbledon champion. The 20-year-old Stephens, meanwhile, faces 92nd-ranked Marina Erakovic, who beat No. 16 Dominika Cibulkova 6-2, 2-6, 6-4 to become the first woman from New Zealand to reach the French Open's third round.
By winning in the second round, Mattek-Sands matched her best effort at Roland Garros. She failed to qualify for the Australian Open in January and arrived in Paris with a 10-8 record this year and a No. 67 ranking.
Li was ranked sixth. Since winning her lone major title, she has lost in the first or second round at four of the eight major events.
"I was a little bit surprised today the way she's hitting," Li said. "Well done for her."
Mattek-Sands' best Grand Slam showing came at Wimbledon in 2008, when she reached the fourth round. The 28-year-old Minnesota native is best known for her funky outfits, such as the one she wore at the finish against Li -- a long-sleeve top with black and white horizontal stripes, a black skirt, black sneakers and -- as the piece de resistance -- black knee-high socks.
"I haven't worn anything too crazy on court for a few years now," Mattek-Sands said. "I feel like my racket has been doing a lot of the talking."
Playing on cozy court 1, nicknamed the bullring, Mattek-Sands appeared on the verge of defeat in the second set when rain prompted a 90-minute delay. She returned whacking winners, including a picturesque crosscourt backhand lob that gave her a break point and control of the final set.
The 20-year-old Stephens also endured two rain delays and said she's still learning how to handle the waiting.
"You literally have nothing to do," she said. "Should I eat? Do cartwheels? You have no idea what to do, so it's just kind of you're lost.
"Last week in Brussels I got my nails done. And then we had chocolate and I watched my mom get makeup. And then I played a match."
Despite the interruptions, Stephens overpowered King from start to finish and enjoyed a 26-1 advantage in baseline winners.
Meanwhile, Oudin was doomed by a weak serve. She won only 19 of 51 service points and holding just once.
Former No. 1 Jelena Jankovic won 12 consecutive games to beat the rain and Garbine Muguruza. Jankovic fell behind early but rallied past Muguruza 6-3, 6-0 shortly before showers interrupted the first matches of the day on 12 other courts.
With temperatures in the mid-50s, Jankovic took the court wearing pink leggings and a long-sleeve pink shirt. She looked uncomfortable at the start, losing the first three games, then won the rest after adjusting to the strokes of Muguruza, a 19-year-old Spaniard.
"She's a great up and coming player," Jankovic said. "She hits the ball very hard, very flat. And especially in the beginning of the match she gave me a lot of trouble. I figured out the way to play against her, and I think I did pretty well."
Jankovic won with steady play from the baseline, while the big-swinging Muguruza committed 29 unforced errors.
Jankovic, seeded 18th, is a three-time semifinalist at Roland Garros. She'll next play 2011 U.S. Open champion Stosur.
The No. 9-seeded Stosur never lost serve but needed nearly an hour to take the first set against Mladenovic. Stosur reached set point for the fourth time on a fluky point with her opponent at the net, hitting a line-drive reflex volley that sent Mladenovic ducking to avoid. The ball kissed the baseline for a winner, and Stosur waved in apology to Mladenovic.
"I ran in thinking she would drop-shot, and she didn't drop-shot," Stosur said. "I don't know what grip I had, what I did, where it landed. I don't know anything. It was very, very lucky, but obviously at a really important time."
Said Mladenovic: "Obviously it was not on purpose, but it was an amazing reflex. I think she won't do it again in her life. We both laughed after it, because it was just an unbelievable one."
Mladenovic then double-faulted to lose the 16-point game. Stosur took a 3-0 lead in the second set and held the rest of the way.
Information from The Associated Press was used in this report.