The fourth-seeded Sharapova overcame six double-faults to defeat Estonian Kaia Kanepi 6-4, 6-1, while the 16th-seeded Williams came back from a 3-0 deficit in the opening set to defeat Britain’s Heather Watson 6-3, 6-1.
In other first-round matches, Australian Samantha Stosur beat Francesca Schiavone of Italy 6-4, 6-2 to set up a second-round clash with the in-form Caroline Wozniacki, who reached the final of the U.S. Open earlier this month.
Other winners included No. 12-seeded Ekaterina Makarova of Russia, who beat Spain’s Garbine Muguruza 6-7 (8), 6-4, 6-4, and No. 15-seeded Andrea Petkovic of Germany, who took out Romanian qualifier Monica Niculescu 2-6, 7-6 (8), 6-4.