NEW YORK, NY, USA - Maria Sharapova kept her perfect record in night matches at the US Open alive on Wednesday night, overpowering Belarusian Anastasiya Yakimova in a match that ended after midnight, 61 61.

Sharapova, seeded No.3, struggled in her first round against Heather Watson on Monday, battling back from a set down to beat the athletic Brit, 36 75 63; she had far fewer problems with Yakimova, improving to 14-0 in her career in night matches at the Open (more specifically 13-0 in night matches on Ashe).

"I played a pretty tricky opponent tonight who didn't play the typical kind of tennis. Sliced a lot, a lot of high balls. Maybe the first couple of games I was a little bit impatient," Sharapova said. "Then I got really steady. I was aggressive. I still felt I could have moved in a little bit more, but overall I played solid."

Sharapova was asked about Venus Williams' withdrawal from earlier in the day. "I hope it's not obviously the end of her career. I still feel like, although she's a bit older, she's still one of the fittest players on tour and one of the most dangerous when she's playing well. It's obviously tough in sport - I always mention how important health is. It's just the way it goes sometimes."

The only other Russian in the Top 15, Vera Zvonareva, also won her opener, albeit in far more difficult fashion. Ranked and seeded No.2 this fortnight, she battled Kateryna Bondarenko in an afternoon marathon but won, 75 36 63.

"I've known Kateryna for a long time and knew she was a dangerous player, so I expected a very tough match," Zvonareva said. "It was a good test for me. I don't think I played my best tennis but I managed to get through this one, and now I have another chance to go out there again and try to do a little bit better."

Zvonareva also discussed playing her way into tournaments. "Usually I'm there by the fourth round. That's where I really pick it up. In any tournament, like starting in the quarterfinals, that's where I'm really picking up my level.

"I'm an all-court player and I can do a lot of things, but it takes time for me to adjust to new surfaces, new conditions. It's always been like this. I can play very well on any surface, but I just need some time. That's why it probably takes me a couple of matches to really get to the level where I want to be."

Next up for Zvonareva will be No.30-seeded Spanish veteran Anabel Medina Garrigues. Zvonareva leads their head-to-head series, 3-1, although in their last meeting, three years ago, Medina Garrigues scored a 63 30 retirement win at an indoor event when the Russian had to retire due to dizziness.

"I don't recall playing her in a long time," Zvonareva said. "Last time we played I think it was maybe four years ago, and I think it was red clay. It's going to be a new day here. I will think about it - it's definitely going to be a tough one."

Other second round winners included seeds Samantha Stosur, Peng Shuai, Julia Goerges, Nadia Petrova, Maria Kirilenko, Flavia Pennetta and Lucie Safarova. Fallen seeds included No.12 seed Agnieszka Radwanska, who lost to Angelique Kerber, 63 46 63; No.14 seed Dominika Cibulkova, who lost to Irina Falconi, 26 63 75; and No.20 seed Yanina Wickmayer, who had to retire in the second set against Alla Kudryavtseva due to a low back injury.

Falconi's match with Cibulkova was moved to Ashe Stadium after the Williams-Lisicki match was cancelled. "When one of the WTA Supervisors pulled me aside and told me I was going to play on Ashe, I needed to go outside and get some fresh air, for sure," Falconi said. "People ask, 'What's it like for a player to be playing on Arthur Ashe?' You can't really explain it. There are no words."

The 21-year-old Falconi, an Ecuadorian-born American, held up an American flag after her win. "I've heard so much about media talking about American tennis, and I wanted to portray there's a huge wave of American players. I strongly believe in all that is USA, and I wanted to represent it and show the world it's coming. It's coming. No need to wait any longer."

Falconi added she has kept the flag in her bag since turning professional.