Defending champion Maria Sharapova defeated Anastasia Pavlyuchenkova 6-4, 6-3 on Thursday to set up a Porsche Grand Prix quarterfinal with top seed Agnieszka Radwanska.
The sixth-seeded Sharapova needed a little over an hour and a half to defeat her fellow Russian, keeping alive her dream of winning the tournament for the third year in a row.
Polish world No. 3 Radwanska was rarely troubled in wrapping up a 6-3, 6-2 win over Italy's Roberta Vinci.
Svetlana Kuznetsova of Russia rallied from a 5-2 first-set deficit to edge second seed Simona Halep of Romania 7-5, 7-6 (4) in the late match.
The 2009 champion will next play former No. 1 Ana Ivanovic, who lost her first set against German wild card Julia Goerges, but recovered to prevail 1-6, 6-2, 6-3.
Carla Suarez Navarro upset the fourth-seeded Angelique Kerber 7-5, 6-4 to knock the last remaining German out of the tournament. The world No. 16 next faces Estonia's Kaia Kanepi on Friday.
Fifth seed Jelena Jankovic rallied after losing the first set to beat Flavia Pennetta of Italy 3-6, 6-2, 6-3 for a quarterfinal against Alisa Kleybanova, who upset the third-seeded Petra Kvitova on Wednesday.
