Beijing - 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 (0/7), 6-4.
Results on Monday at the China Open, a $2.205m ATP event and $4.8m WTA tournament played on outdoor hard courts at The Beijing Tennis Centre (seedings in parentheses):
Marius Copil, Romania, def. Marin Cilic (4), Croatia, 3-6, 7-6 (0), 6-4.
Zhang Ze, China, def. Wu Di, China, 6-4, 6-1.
Florian Mayer, Germany, def. Fabio Fognini, Italy, 6-1, 6-2.
Carlos Berlocq, Argentina, def. Marinko Matosevic, Austria, 3-6, 6-2, 6-3.
Alexandr Dolgopolov (6), Ukraine, def. Guillermo Garcia-Lopez, Spain, 6-0, 6-4.
Sam Querrey, United States, def. Fernando Verdasco, Spain, 5-7, 6-3, 6-4.
Kevin Anderson, South Africa, def. Brian Baker, United States, 5-7, 6-3, 6-1.
Victoria Azarenka (1), Belarus, def. Alize Cornet, France, 6-1, 6-0.
Maria Sharapova (2), Russia, def. Simona Halep, Romania, 7-5, 7-5.
Lara Arruabarrena-Vecino, Spain, def. Zheng Jie, China, 6-2, 6-4.
Sabine Lisicki, Germany, def. Anabel Medina Garrigues, Spain, 6-3, 5-7, 6-2.
Polona Hercog, Slovenia, def. Anastasia Pavlyuchnkova, Russia, 5-7, 6-4, 3-0, retired.
Sorana Cirstea, Romania, def. Sofia Arvidsson, Sweden, 6-2, 6-3.
Caroline Wozniacki (10), Denmark, def. Chanelle Scheepers, South Africa, 7-5, 6-7 (8/10), 6-2.
Elena Vesnina, Russia, def. Tamira Paszek, Austria, 7-6 (7/5), 6-2.
Carla Suarez Navarro, Spain, def. Petra Kvitova (4), Czech Republic, 6-3, 6-2.
Ana Ivanonic (11), Serbia, def. Varvara Lepchenko, United States, 4-6, 7-5, 6-1.
Peng Shuai, China, def. Yaroslava Shvedova, Kazakhstan, 5-7, 7-5, 6-2.