The 31-year-old received a wildcard invitation into the event and is looking to rebuild her ranking after being diagnosed with the auto-immune disorder Sjogren syndrome.

The American made it to the quarter-finals in Miami on her return to action last week and required 79 minutes to get past the 44th-ranked Benesova.

But Williams, who won the Charleston event eight years ago, will face a tougher test in the shape of seventh-seed Jelena Jankovic in the second round.

The Serbian received a bye past the first round.

"This is great for me to be in another match and to be in the second round," Williams said. "For me it's just about having energy at this point. I try not to worry about tomorrow.

"I'm very happy I'm on the right road, but I'm very unhappy I didn't do more in Miami.

"That's the past. There's so many opportunities going forward and I try to focus on the forward and focus on every day and today's win takes me closer."

Her younger sister Serena was already in second-round action, and made light work of Russian Elena Vesnina as she won 6-3 6-4.

Stosur through

Also in the second round, second seed Samantha Stosur saw off wildcard Jamie Hampton 6-0 7-5 while Russian Vera Zvonareva had an even easier time in seeing off Kateryna Bondarenko 6-1 6-1.

Eighth-seeded Anastasia Pavlyuchenkova had to come from behind to beat Eleni Daniilidou 3-6 6-4 6-4 but there was no way back for number 10 Anabel Medina Garrigues, who exited with a 7-5 6-3 loss to Anastasia Rodionova.

The remaining first round matches saw number 12 Yanina Wickmayer, 13th seed Nadia Petrova, and number 17 Marina Erakovic, advance along with Varvara Lepchenko, Anna Tatishvili, Jill Craybas, Anna Tatishvili and Yaroslava Shvedova.