Top seed Caroline Wozniacki of Denmark advanced in straight sets while second seeded serbian Jelena Jankovic was upset in the quarter-finals of the WTA Family Circle Cup on Friday.

Wozniacki reached the semi-finals with a 6-3, 6-4 win over Russian Nadia Petrova while Daniela Hantuchova rallied to beat Jankovic 1-6, 6-3, 6-3.

Jankovic won the first three games of the opening set and took the set 6-1. But then she fell apart losing the first four games of the second set.

"I played really well in the first set and I played really aggressive," said Jankovic. "But then I just stopped and I especially had trouble hitting my backhand."

It marks the first time in three years that Hantuchova has beaten a top ten ranked player.

"Definitely, I felt very good on the court today, even though the first set was not easy," Hantuchova said.

Hantuchova next faces Aussie Samantha Stosur who beat Peng Shuai of China 6-4, 6-1.