Top-ranked Victoria Azarenka and No. 2 Maria Sharapova both advanced to the second round of the China Open on Monday.
Azarenka beat Alize Cornet of France 6-1, 6-0, while Sharapova defeated Simona Halep of Romania 7-5, 7-5.
Last week in Tokyo, Azarenka withdrew from the tournament after a bout of dizziness in the third round.
Azarenka has won four times this year, including the Australian Open. Sharapova won her first Grand Slam title in four years at the French Open.
In the first round of the men's draw, fourth-seeded Marin Cilic of Croatia, last year's runner-up, lost to Marius Copil of Romania 3-6, 6-7 (0), 6-4.