Nadia Petrova and Jelena Jankovic, who were champions of the Family Circle Cup in 2006 and 2007, respectively, both won their matches Thursday to advance to today's quarterfinals.
Jankovic, the No. 2 seed in this year's tournament and ranked No. 7 in the world, defeated Evgeniya Rodina, 6-3, 6-1. Petrova, the No. 6 seed, defeated No. 12-seeded Aleksandra Wozniak, 6-2, 6-4.
Petrova will face top-seeded Caroline Wozniacki at 1 p.m. today, while Jankovic will face No. 8 seed Daniela Hantuchova, who beat Angelique Kerber, 6-7 (6), 7-5, 6-3.
Jankovic and Hantuchova are scheduled to play at 11 a.m.
In other matches played during the day, No. 7 Vera Zvonareva, runner-up in the 2008 Family Circle Cup, defeated No. 9 Alona Bondarenko, 6-2, 6-1, and No. 13 Melanie Oudin defeated qualifier Christina McHale, 6-4, 6-0.
Zvonareva and Oudin will meet at 7 p.m.
Jankovic said she played much better than she did during a first-round victory over Edina Gallovits.
"I'm pretty pleased with the way I played today," she said. "I think I was hitting the ball much better and moved much better, so I hope to continue this."
Hantuchova, ranked No. 24, sounded a little displeased about playing a match that lasted almost three hours and then having to turn around and play Jankovic in today's early match.
"It's kind of tough to recover and get ready so soon," Hantuchova said. "I just finished a match, and having to play so early tomorrow doesn't really help."
Hantuchova said Kerber was scoring winners from "unbelievable positions."
"I thought I did well to come back to the tiebreaker there," she said. "I made a few mistakes, but still I felt like I really had to stay in the match and kept fighting really hard because she was playing very well. At the end, I felt like maybe physically I was a little better than her and that was the deciding thing."
Petrova, ranked No. 18, said she will have to be both focused and patient against Wozniacki, the 19-year-old from Denmark who is No. 2 in the world rankings.
"She doesn't really go much for the winners, so it's going to be a lot of long rallies," Petrova said. "So patience is the No. 1 key, and hopefully my serve is going to work well so I can get some free points on my serve. Don't pay any attention to the score. Just go out there and give everything as much as possible to win the match."
Petrova said she was happy with her performance against Wozniak.
"I played well. I served very well. I returned very well," Petrova said.
Zvonareva, No. 22 in the world, said she felt like she was fresher than Bondarenko, who played a three-hour match Wednesday.
"I was trying to pump myself up and play faster, make the rallies last longer and tougher for her, and I think I was successful at it today," Zvonareva said.
Oudin, No. 36 in the world, had a battle in the opening set against McHale, who advanced earlier when Victoria Azarenka, the No. 3 seed, withdrew with an injury.
"The first set I started off really well. I got up 3-0, and then I got a little bit tight and started thinking too much about who I was playing, a girl younger than me, another American I was supposed to beat," Oudin said. "I was thinking too much about that and then I started double faulting, making too many errors and letting that get into my mind.
"Once my coach came out and talked to me, I didn't lose a game after that. I just calmed down and relaxed and the second set was really quick. I just made my shots and was able to win."
Oudin noted that she faced Zvonareva a few weeks ago and Zvonareva won handily.
"I know going into this next one I'm going to have to play really well to be able to win," she said. "I think it's going to be another tough one."