Williams, seeded fifth, notched her 16th consecutive match win with a 6-2, 6-3 romp over Francesca Schiavone in a second-round match. She is going for her fourth consecutive tournament title. If she wins the German Open, she'll take home $196,600.

No. 7-seeded Elena Dementieva and eighth-seeded Marion Bartoli also had impressive wins Tuesday. Dementieva stopped Kateryna Bondarenko 6-1, 6-2 and Bartoli was in complete control in a 6-0, 6-3 win over Lucie Safarova.

But ninth-seeded Patty Schnyder was ousted by Vera Dushevina 6-2, 6-3 and 12-seeded Nicole Vaidisova lost 4-6, 6-1, 6-2 to Gisela Dulko in first-round action.

In other first-round matches Tuesday, Victoria Azarenka, beat Casey Dellacqua 6-2, 6-2; and Anabel Medina Garrigues got past Tathiana Garbin 3-6, 7-5, 2-2, as Garbin retired with left thigh injury in the third set.

Additional opening-round wins came for Catalina Castano, Maria Kirilenko, Alisa Kleybanova, Shuai Peng, Zi Yan and Akgul Amanmuradova.