American Venus Williams rallied Sunday for another win at the at the Sony Ericsson Open, her first tournament since last year's U.S. Open.

Williams survived a match point at 5-4 in the third set to beat Aleksandra Wozniak of Canada 4-6, 6-4, 7-6 (7-5) in a third round match lasting nearly three hours.

Sidelined for sixth months because of Sjogren's syndrome -- an auto-immune disease that causes fatigue and joint pain -- Williams made the field as a wild card at a tournament she's won three times.

She dropped only three games to beat Kimiko Date-Krumm in her return Wednesday and knocked off reigning Wimbledon champion and world No. 3 Petra Kvitova in three sets on Friday.

Williams had no idea she was down match point -- "Thank God I'm oblivious to the score a lot of the time" -- and said she has one goal that keeps her motivated in tough spots: the upcoming London Olympics.

"I kept thinking about the Olympics and how I need my points," she said. "When things look bleak, I think about the Olympics."

Sunday's final third-round match at the $4.828 million tournament is being played between top-seeded Victoria Azarenka and Heather Watson.

Earlier, fifth-seeded Agnieszka Radwanska eased past Silvia Soler-Espinosa 6-1, 6-2 and seventh-seeded Marion Bartoli edged Simona Halep 6-4, 7-6 (8-6).

Also, No. 15 seed Ana Ivanovic beat Daniela Hantuchova 6-2, 7-6 (7-2); 16th seed Dominika Cibulkova raced past Zheng Zie 6-2, 6-0; 22nd-seeded Maria Kirilenko topped Ksenia Pervak 6-2, 6-1; and Garbine Muguruza Blanco knocked off 24th-seeded Flavia Pennetta 6-2, 1-6, 7-6 (8-6).