Venus Williams can't remember the last time she took on younger sister Serena on the tennis court. The next time could be coming up soon at the Family Circle Cup.

Venus and Serena both reached the quarterfinals of the Family Circle Cup on Thursday with straight set victories. Venus defeated Anastasia Rodionova 75, 6-2 on center court shortly after Serena ousted Marina Erakovic, 6-2, 6-2. Should the sisters win on Friday, it would set up a Saturday showdown in the semifinals.

"If we both get to the semifinal," Venus said, "I guess the best Williams will win."

Most times, that's been Serena. She holds a 13-10 edge in the family rivalry, although the two haven't met since Serena took the title at the 2009 WTA Championships in Qatar.

Serena holds a 7-5 advantage over her sister at grand slam events and has won six of the eight times the two of faced off for major titles.

Serena also wasn't yet prepping to face the player on tour she knows the best, although she was rooting for the matchup. "I have to win another match," Serena said. "I really hope we both get there, so we'll see."

Serena Williams, ranked 10th in the world, might have the easier time of it. She'll go up against 2009 Family Circle winner Sabine Lisicki, who stands 13th in the WTA rankings. The last time the two met, Williams won on the way to the Bank of the West title last summer.

"It can only get better," Lisicki said.

Venus, 87th in the world, hadn't played in more than six month until last week's Sony Ericsson Open. She could face the Family Circle's No. 2 seed and reigning U.S. Open champion Samantha Stosur.

Stosur faces Galina Voskoboeva on Thursday night.

Other winners Thursday included No. 4 seed Vera Zvonereva, No. 13 seed Nadia Petrova and No. 9 seed Lucie Safarova. Third-seeded Marion Bartoli fell to the 14th seed, Polona Hercog, who overcame a 4-2 deficit in the third set to advance.

The Williams sisters are each playing well enough to win their first clay-court event of the season. Venus, the 2004 champion here, has only dropped one set in three matches and has reached the final eight in each of her two tournaments since she came back.

Serena won both her matches in straight sets and has gotten stronger since the week began.

That was certainly the case in Serena Williams' first meeting with Erakovic.

Serena Williams and Erakovic traded ground strokes early on, with the 24-year-old New Zealander prevailing in a game that took nearly 15 minutes to play and left the first set tied at 2.

Williams, annoyed she played through seven deuces and still lost, then cranked it up and won the final four games of the set.

Erakovic was overmatched the rest of the way, often watching from the baseline as Williams' shots flew past for winners. At one point, Williams swung and missed as Erackovic's lob shot flew over, yet caught up with the ball moments later on the bounce and flipped it over the net for a winner. Williams switched sides with a huge grin on her face.

"I'm really excited to be playing some matches here because it really gives you confidence in the things that you want to work on, not just for today and tomorrow, but the rest of the clay-court season," Williams said.

Williams had aces clocked at 120 and 121 mph in the final set. Erakovic double faulted to end the match.

Williams won 10 of the last 12 games to advance.

Williams said she was more comfortable in her second match on clay, moving better and reacting more crisply during the longer points that come with the slower surface.

"So I felt good," Williams said. "I love the clay."

It doesn't always love her back, especially at Roland Garros. Williams, a 13-time grand slam titlist, won her only French Open crown in 2002. She lost in the semifinals the next year, and hasn't made it past the quarterfinals in five trips since. Paris is "my favorite city in the world," Williams said. "I hate leaving there."

So imagine how much it must gall the ultra-competitive Williams when she leaves without the victory.

First things first, though, and that's trying for a second Family Circle crown.

Venus Williams is also a past champ here, winning in 2004. She's met each test so far this week, including Rodionova, the 29-year-old Australian.

Venus closed strongly in both sets. She trailed 4-2 in the opening set before winning five of the final six games. Williams won the last four games of the second set to close out the match.

Williams says the past six month away from the game gave her a healthier perspective on competition. Before she worried over how well her serve would work or if she'd land her ground strokes. The disease has "taken my mind off whether or not I can play tennis," Venus said. "Like now I know I can play. So it's a different way of looking at things."