Wozniacki won 69 percent of the points in a 6-1, 6-0 win over Vania King. Wozniacki had 23 winners against eight errors and won 58 percent of the points when King was serving.
Fourth-seeded Venus Williams dropped a first-set tiebreaker before posting a 6-7 (6-8), 6-0, 6-4 win over Sandra Zahlavova. The first set took 79 minutes and Williams needed three hours to advance to the third round. She had 38 winners against 43 unforced errors.
No. 6-seeded Francesca Schiavone was forced into extra third-set games before escaping with a 6-3, 5-7, 9-7 victory over Rebecca Marino and eighth-seeded Victoria Azarenka was a 6-4, 6-4 winner over Andrea Hlavackova.
Four seeded players were beaten Wednesday. Qualifier Vesna Manasieva ousted 15th-seeded Marion Bartoli 3-6, 6-3, 6-0 and Julia Georges topped No. 20 Kaia Kanepi 6-4, 3-6, 6-4. Also, Anastasija Sevastova defeated 21st-seeded Yanina Wickmayer 6-4, 6-2 and Monica Niculescu eliminated No. 32 Tsvetana Pironkova.
Ninth-seeded Li Na was a 6-3, 6-2 winner over Evgeniya Rodina and former No. 1s Justine Henin, seeded 11th this year, and No. 14 Maria Sharapova advanced to the third round with straight-set wins.
Other seeded winners Tuesday were No. 23 Svetlana Kuznetsova, 29th-seeded Dominika Cibulkova and No. 30 Andrea Petkovic. Unseeded Barbora Zahlavova Strycova and Chanelle Scheepers also earned third-round berths.