Williams, No. 2 in the world, blew by Ekaterina Makarova 6-0, 6-4. She took the first set in 25 minutes, yielding only three points on serve in the set and 11 in eight service games overall.
Clijsters, seeded eighth, stopped Karolina Sprem 6-3, 6-2 and didn't drop serve while the 17th-seeded Henin topped Kristina Barrois 6-3, 7-5. Henin fought through 21 unforced errors (against 38 winners) and lost her serve three times.
No. 4-seeded Jelena Jankovic needed three sets to beat Aleksandra Wozniak 4-6, 6-2, 6-4, but 12th-seeded Nadia Petrova breezed past Yung-Jan Chan 6-3, 6-4.
Angelique Kerber rallied for a 3-6, 6-3, 6-4 victory that ousted 13th-seeded Shahar Peer, while Regina Kulikova eliminated 30th-seeded Yaroslava Shvedova and Jarmila Groth defeated 33rd-seeded American Melanie Oudin.
Marion Bartoli, the 11th seed, moved on in a walkover, and No. 15-seeded Yanina Wickmayer advanced over Kirsten Flipkens 7-6 (11-9), 6-4.
Also advancing out of the second round Wednesday were 21st-seeded Vera Zvonareva, No. 26 Alisa Kleybanova, 27th-seeded Maria Kirilenko and 28th-seeded Alona Bondarenko. No. 24-seeded Daniela Hantuchova finished off a first-round win suspended Tuesday because of darkness.
Other winners were Tsvetana Pironkova and Greta Arn.