The other women's quarter-finals saw in-form Kaia Kanepi hammer seventh seed Anastasia Pavlyuchenkova 6-0 6-3 while sixth seed Jelena Jankovic beat Russian Nina Bratchikova 6-3 6-2.
Men's top seed Andy Murray was forced to recover from a set down for the second day in succession to beat Luxembourg's Gilles Muller.
The world number four lost the opening set 6-4 after a dismal final service game but took the second on a tie-break and powered through the decider to win 4-6 7-6 (7/4) 6-0.
The Scot will next face Cypriot Marcos Baghdatis, a 6-3 6-4 winner over fifth seed Kei Nishikori today.
Third seed Alexander Dolgopolov was another player to face a stern test before eventually overcoming Russia's Igor Andreev 6-7 (3/7) 7-6 (11/9) 6-2.
Second seed Gilles Simon beat Sydney teenager James Duckworth 6-3 7-5 but Bernard Tomic kept home hopes alive with a routine 6-1 6-2 win over Japan's Tatsuma Ito.
Radek Stepanek beat Jarkko Nieminen 7-6 (7/4) 6-2 while Santiago Giraldo earned a 6-4 6-4 success against Philipp Petzschner.