Australians Samantha Stosur and Anastasia Rodionova have advanced to the third round of the WTA Tour’s Charleston tournament after both recorded straight sets victories on Tuesday.

No.2 seed Stosur – the highest seed after Pole Agnieszka Radwanska withdrew before the tournament with a back injury – beat American Jamie Hampton 6-0 7-5 in her second round clash.

The 98th-ranked Rodionova meanwhile had her work cut out for her against clay court specialist Anabel Medina Garrigues, who boasts more WTA titles on the surface than any other active player having won 10.

But Rodionova prevailed with a 7-5 6-3 upset over the 10th-seeded Spaniard.

Also on Tuesday Venus Williams beat qualifier Iveta Benesova of the Czech Republic 6-4 6-3, bouncing back from her quarter-final loss at Key Biscayne last week.

“This is great for me to be in another match and to be in the second round,” she said. “It was a good start.”

The Charlston event is Williams’ first clay-court tournament in months. She withdrew from last year’s US Open after being diagnosed with a fatigue-causing autoimmune disease, then returned last week and won four matches in Miami before losing to eventual champion Radwanska in straight sets.

Williams, currently ranked 87 in the world, acknowledges she is thinking about getting her ranking up so she can qualify for the London Olympics this summer.

“I’m very happy I’m on the right road, but I’m very unhappy I didn’t do more at Key Biscayne,” she said.

Sister Serena is seeded fifth this week and plays in Tuesday night’s featured match against Elena Vesnina of Russia. The Williams sisters could meet in Saturday’s semi-finals.

In other action fourth-seeded Vera Zvonareva of Russia eliminated Kateryna Bondarenko 6-1 6-1 and No.8 seed Anastasia Pavlyuchenkova ousted Eleni Daniilidou 3-6 6-4 6-4, while Belgium’s Yanina Wickmayer, seeded 12, defeated Vania King of the US 6-4 6-3.

Thirteenth seed Nadia Petrova and American Jill Craybas also advanced. Petrova beat Mariana Duque-Marino 6-1 6-2, and Craybas eliminated Akgul Amanmuradova 7-6 (7-2) 7-6 (8-6).