American Melanie Oudin, who came out of nowhere to reach the quarterfinals of the 2009 US Open, found it hard to carry the burden of high expectations and fell to the recently-married Alona Bondarenko in the second round this year. The 18-year-old Oudin made 38 unforced errors during her 6-2 7-5 loss to seed No.29 Bondarenko.

Second seed and defending champion Kim Clijsters had an easy task against Sally Peers, a 19-year-old qualifier ranked 201. Clijsters advanced to the third round with a 6-2 6-1 victory over Grand Slam debutant Peers, who recorded a 6-0 6-1 win over Aleksandra Wozniak in the first round.

Third-seeded Venus Williams struggled early in her match against 193rd-ranked qualifier Rebecca Marino, but beat her 7-6(3) 6-3.

French Open runner-up Samantha Stosur, seeded fifth, reached the third round of the US Open for the first time, even though it’s her seventh appearance at the tournament. Stosur defeated Anastasia Rodionova 6-1 6-4.

Sixth seed Francesca Schiavone, 2010 French Open champion, quickly won her match against fellow Italian Maria Elena Camerin 6-2 6-1. Schiavone has now lost a total of just four games to advance to the third round of the US Open. (photos: © Neal Trousdale)

Ana Ivanovic needed just 56 minutes to beat seed No.21 Zheng Jie and advance to the third round of the US Open.

The world No.40 Ivanovic is building on the momentum started in Cincinnati recently, which was abruptly interrupted by a left foot injury. Luckily, Ivanovic is not showing signs of it and she displayed impressive form to avenge the 2008 Wimbledon defeat to Zheng, who then became the third-lowest ranked player to beat a reigning world No.1.

Tenth seed Victoria Azarenka could not bear the hot weather in New York and 34 minutes into her second round match against Gisela Dulko, while trailing 5-1, Azarenka collapsed and had to be taken off the court in a wheelchair and was later transported to the hospital. Also, it didn’t help that Azarenka was wearing an all-black dress in the sun (the dress  Serena would have worn hadn’t she withdrawn).

Dulko, who is now through to the third round, commented on the weather conditions: "It's really hot, really humid. You sweat so much, sometimes it's impossible to hold the racquet."

Update: It has been revealed that heat was not the main reason for the accident, but Azarenka's fall in the gym that happened before the match.

Here's Azarenka's statement:

I was warming up in the gym prior to my match against Gisela Dulko when I fell while running a sprint. I fell forward and hit my arm and head. I was checked by the medical team before I went on court and they were courtside for monitoring. I felt worse as the match went on, having a headache and feeling dizzy. I also started having trouble seeing and felt weak before I fell.

(photo: © Neal Trousdale)

Seed No.14 Maria Sharapova dropped the first set against Jarmila Groth in the first round of the US Open but fought back to eventually win 4-6 6-3 6-1.

The world No.60 Groth, who reached the fourth round at this year's French Open and Wimbledon, wasn’t able to challenge the former champion Sharapova all the way and in the third set Groth's meltdown was evident.

Groth committed considerably more unforced errors than Sharapova, 48 compared to Sharapova’s 17. Groth scored 24 winners to Sharapova’s 19, but 13 of those came in the first set.

And just a quick fashion note – the Nike day dress which looked questionable in the picture looks awesome on Sharapova, it perfectly follows the shape of her body and now there’s absolutely nothing that I don’t like about the dress.

Top seed Caroline Wozniacki played the last match of the night and scored her 14th straight win in the first round of a major with a 6-1 6-1 victory over American wildcard Chelsey Gullickson. (photo: © Neal Trousdale)

Fourth seed Jelena Jankovic had a tough opening match at the US Open against world No.96 Simona Halep of Romania. As Jankovic said, she wasn’t playing her best tennis, but was able to get through.

The 2008 US Open finalist Jankovic lost the first set and found the 18-year-old Halep serving for the match at 5-4 in the decider. Halep was actually two points away from victory, but Jankovic then broke her serve and won all the remaining games to advance to the second round. Final score: 4-6 6-4 7-5.

Halep made her Grand Slam debut at this year’s French Open and lost in the first round as well.

Seed No.11 Svetlana Kuznetsova was pushed to three sets, 6-2 4-6 6-1, in her first round match against Japanese veteran Kimiko Date Krumm, whose last match in the US Open’s main draw prior to her this year’s appearance was a loss in the first round in 1996.

Kateryna Bondarenko sent home eighth-seeded Li Na with a 2-6 6-4 6-2 victory. Li, who reached at least the fourth round in her last three appearances at the US Open, blamed the heat for the defeat and her inability to cope with it. (photo: © Neal Trousdale)

Daniela Hantuchova avenged her last week’s 7-6(4) 7-6(2) defeat to Dinara Safina by beating the Russian 6-3 6-4 in the first round of the US Open. Safina has now lost in the first round of a Grand Slam for the second straight time, at Roland Garros and now at the US Open, while she skipped Wimbledon with a lower back injury.

The former world No.1 Safina, currently ranked 50th, fought hard in the match against seed No.24 Hantuchova, and had a chance to level at 5-5 in the second set, but Hantuchova stayed in there and Safina’s long return handed Hantuchova the victory in the end.

Fifth seed Samantha Stosur lost the first set to Elena Vesnina, and dropped serve right in the beginning of the second set, before breaking right back and eventually winning the set in a tiebreak to finally storm through the decider. Final score: 3-6 7-6(2) 6-1.

Defending champion Kim Clijsters cruised through the first set against world No.104 Greta Arn in just 18 minutes, without losing a single game. In the second set, however, the second-seeded Belgian found herself in a 4-0 deficit before winning 12 straight points (three games) and breaking Arn's serve in the 10th game and again in the last game to close out the match with the score 6-0 7-5.

The victory marks Clijsters’ 15th successive win at the US Open. The streak started at the 2005 US Open, which Clijsters won. Then she didn’t compete at the tournament until 2009, the year when she had an amazing run to another US Open title.

French Open champion Francesca Schiavone eased into the second round of the 2010 US Open with a 6-1 6-0 victory over Ayumi Morita. American darling, Melanie Oudin, is also through. She defeated Olga Savchuk 6-3 6-0. (photo: © Neal Trousdale)