Top-ranked Victoria Azarenka and No. 2 Maria Sharapova reached the China Open quarterfinals Thursday with straight-set wins.

Azarenka easily beat Elena Vesnina of Russia 6-3, 6-3, while Sharapova defeated Slovenian qualifier Polona Hercog 6-0, 6-2.

Azarenka will face Romina Oprandi of Switzerland, while Sharapova will play Angelique Kerber of Germany. Kerber beat former No. 1 Caroline Wozniacki of Denmark 6-1, 2-6, 6-4.

''I played really well in the beginning and got a little tense in the second set,'' Sharapova said. ''But I felt like I really needed that challenge.''

Sharapova won her first Grand Slam title in four years at the French Open

Azarenka is hoping to rebound from last week in Tokyo when she withdrew from the tournament after a bout of dizziness in the third round. Azarenka has won four times this year, including the Australian Open.

In men's singles, Mikhail Youzhny of Russia defeated Kevin Anderson of South Africa 6-3, 6-3 and Zhang Ze of China beat fifth-seeded Richard Gasquet of France 6-4, 3-6, 6-4.

Also, Feliciano Lopez of Spain beat Yen-Hsun Lu of Taiwan 6-3, 7-6 (7).

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