Romanian teenager Sorana Cirstea [ Images ] upset third seed Anna Chakvetadze [ Images ] 6-2, 1-6, 6-2 in the second round of the Family Circle Cup on Tuesday.

It was the first WTA Tour victory over a top 10 player for the 18-year-old, who won a three-set match against American Vania King [ Images ] on Monday and is ranked 86th in the world.

"Until now, I was saying hardcourt was my favourite surface but I think I'm going to change my mind," a beaming Cirstea told reporters.

"I like the green clay better than red clay. It really suits my game because I am really aggressive.

World number six Chakvetadze had a first-round bye.

"She just pushed the ball back and I made mistakes," the Russian said.

Sixteenth seeded Michaella Krajicek of the Netherlands also lost, going out 6-3, 3-6, 6-4 to Alize Cornet [ Images ] of France [ Images ] in a first-round match.

Slovakia's Dominika Cibulkova [ Images ], the 15th seed, retired with a back injury trailing 6-4, 1-0 in a first-round encounter with Anastasia Rodionova of Russia [ Images ].

In second-round action, fifth-seeded American Serena Williams [ Images ] brushed aside Argentina's Gisela Dulko [ Images ] 6-3, 6-4 and Frenchwoman Marion Bartoli [ Images ], the sixth seed, scraped past Casey Dell'Acqua of Australia [ Images ] 7-5, 4-6, 6-1.

Eighth-seeded Dinara Safina [ Images ] of Russia swept past Spaniard Lourdes Dominguez Lino 6-1, 6-4 and 10th seed Agnes Szavay [ Images ] of Hungary edged Ai Sugiyama [ Images ] of Japan [ Images ] 7-5, 3-6, 6-4.

Szavay will next meet Safina who reached the Family Circle Cup final in 2007 where she lost to Serb Jelena Jankovic [ Images ].

"(Dominguez Lino) had already played one match in the tournament and the key for me was to not give her any time," Safina said.

Top seed Jankovic and second-seeded Russian Maria Sharapova [ Images ] received first-round byes and will play on Wednesday. Jankovic faces American qualifier Alexandra Stevenson and Sharapova takes on American Bethanie Mattek [ Images ].