Meanwhile, Maria Sharapova is also through to the last eight after seeing off world No 24 Klara Zakopalova in straight sets.
In a contest that featured nine breaks of serve, the No 3 seed posted a 6-3 6-3 victory over her 30-year-old opponent from the Czech Republic.
The match was much closer than the scoreline suggests, with the opening game on Sharapova's serve needing 16 points before the Russian was able to hold.
In all, Sharapova won five of her service games after facing break points against, and she finally crossed the finishing line after 88 minutes on court.
She now meets the No 8 seed Sam Stosur of Australia who ended the challenge of Russia's two-time Grand Slam champion Svetlana Kuznetsova 6-4 7-5.
