Twice former champion Venus Williams raised her game after some ragged early play to defeat Romanian Ioana Raluca Olaru and advance into the third round of the US Open on Wednesday.
Williams had six double faults and committed 15 errors in the opening set but settled down to win the match 6-4 6-2 in Arthur Ashe Stadium.
"I missed a few shots that were easy, but ultimately, it's important to get to the next round," said Williams. "I always feel like my game will be there. I'm not stressed out on a few shots."
Williams, seeded 12th, was joined in the third round by top seed Justine Henin and fifth seed Ana Ivanovic. In the men's competition, eighth seed Tommy Robredo of Spain advanced, as did 2000 champion Marat Safin.
Top seed Roger Federer was scheduled to play Chile's Paul Capdeville on Arthur Ashe Stadium later on Wednesday.
Williams had surged to a 5-2 lead in the opening set before 18-year-old Olaru, making her first U.S. Open appearance, broke in the ninth game to claw back to 5-4.
The American immediately broke back to love to win the set and then settled down to ease through the second.
Olaru said Williams, champion in 2000 and 2001, could be poised to claim her third title at Flushing Meadows.
"I think she's in pretty good shape," said the Romanian. "And she's motivated as always. But all of the top players are motivated. It's going to be a tough battle but she can do it."
Henin took a while to find her game before dispatching Bulgarian qualifier Tsvetana Pironkova 6-4 6-0.
"I just go step by step and try to build my confidence day after day," said Henin, the 2003 champion. "In a grand slam, you have to be strong, win seven matches. It's tough. It's long.
"You need to be consistent for two weeks. Little mistakes can make a big difference so you need to be aware all the time."
Ivanovic beat Aravane Rezai of France 6-3 6-1 and will play Russian Vera Dushevina in the third round.
"I was a little bit nervous," said Ivanovic. "Then as the match went on I got a little bit in the rhythm and took my opportunities."