Fourth seed Agnieszka Radwanska suffered a shock defeat to China's world number 39 Peng Shuai and became the first high-profile casualty of the US Open in the women's category.
The Pole, who has failed to advance beyond the last 16 in nine visits to New York, lost 6-3, 6-4 to Shuai. Radwanska said that she did not play bad, adding that she thinks it was just Shuai's day. She said that she could of course do something different or try something else, but added that she really tried her best and was fighting till the end.
Fifth seed and 2006 champion Maria Sharapova survived the loss of the first set to see off world number 95 Alexandra Dulgheru 4-6, 6-3, 6-2. But American 21st seed Sloane Stephens also suffered a shock defeat, beaten 5-7, 6-4, 6-2 by Sweden's Johanna Larsson, The BBC reported.
Sharapova said that they started under the sun and finished under the lights, adding that it was tricky conditions, a tough opponent so she is very happy that she was able to come back and come through and win this match.
Stephens said that she missed opportunities, adding that she didn't take advantage of the times she could have and that is definitely something she will look back on, but she won't dwell on it too much. She said that there is room for improvement and she can do a lot of things better.
Two-time champion Venus Williams, seeded 19th for in this year's draw, made the third round for the first time in four years as she beat Switzerland's Timea Bacsinszky 6-1, 6-4. The American will play Italian 13th seed Sara Errani next.
Former world number one Caroline Wozniacki eased aside Grand Slam debutant Aliaksandra Sasnovich of Belarus 6-3 6-4 to set up an intriguing meeting with Germany's Andrea Petkovic, who she beat in the 2011 quarter-final.
Dane Caroline Wozniacki, seeded 10th, beat Aliaksandra Sasnovich 6-3, 6-4. She said that the Belarusian was not an easy opponent, adding that Sasnovich is young and hungry.
Wozniacki added that Sasnovich did not have anything to lose, so she was going for her shots.
Romanian tennis ace Simona Halep defeated Slovakian Jana Cepelova 6-2, 6-1 to advance to round three of the US Open. The world number two said that she started a little bit too slow, but then she started to be more aggressive and hit the ball.
Halep, who won in 56 minutes, said that she feels great now that she could win so fast because it's so hot outside.