The American will next play Olga Govortsova of Belarus, who upset Italian 14th seed Francesca Schiavone with a 6-4 6-4 victory.

CNN: STORY HIGHLIGHTS

In the Barcelona WTA tournament, Olga Govortsova of Belarus continued her fine run with a hard-fought 7-6 6-7 6-2 win over home player Laura Pous in the second round.

CNN: STORY HIGHLIGHTS

Eighth seed Victoria Azarenka made an early exit after she retired due to a thigh injury when leading Timea Bacsinszky 6-4 2-3, while Ana Ivanovic swept past Olga Govortsova 6-0 7-5.

BBC: Britain's Andy Murray eases past Mathieu at China Open