Samantha Stosur continued her build-up to next month’s French Open with a second round win in the WTA claycourt tournament in South Carolina.

Stosur, who won the same tournament in 2010, defeated Kazakhstan’s 2012 French Open quarter-finalist Yaroslava Shvedova 6-3 5-7 6-1 to set up a clash with Lucie Safarova after the ninth seed beat Virginie Razzano in three sets.

Safarova has beaten 2010 French Open finalist Stosur in eight of their 10 career meetings, including the past five in straight sets.

Meanwhile defending champion Serena Williams was downed in straight sets by world No.78 Jana Cepelova at the Family Circle Cup.

Cepelova defeated world No.1 Williams 6-4 6-4 and will face Russia’s Elena Vesnina in the third round.

Williams was chasing a third straight title in Charleston.

“I am really just dead,” said the 32-year-old Williams.

“I need some weeks off where I don’t think about tennis and can kind of regroup. I’ve had a long couple of years.”

Williams was fresh off winning her sixth Miami title and 59th singles crown after beating world No.2 Li Na, of China, on the weekend.

“I actually made the turnaround really good,” Williams said. “Obviously things didn’t go great out there.”

The French Open runs from May 25 to June 8.