Paris - Top-seeded Sara Errani of Italy had little trouble reaching the Open GDF Suez quarter-finals on Thursday, leading 4-0 in the first set when Magdalena Rybarikova of Slovakia retired with a stomach complaint.
Errani will meet Carla Suarez Navarro of Spain in the last eight, after she upset eighth-seeded Klara Zakopalova of the Czech Republic 6-4, 6-3.
There were other second-round upsets, with Dutchwoman Kiki Bertens beating No 4 Dominika Cibulkova of Slovakia 7-5, 6-4, and Frenchwoman Kristina Mladenovic defeating Yanina Wickmayer of Belgium 6-4, 6-4.
Bertens next plays No 6 Lucie Safarova of the Czech Republic, after she got the better of Alize Cornet of France 6-2, 4-6, 6-2.
Mladenovic takes on No 2 Petra Kvitova of the Czech Republic in the quarters.
Results from the fourth day of the WTA Paris Open on Thursday (x denotes seeded player):
Sara Errani (ITA x1) bt Magdalena Rybarikova (SVK) 4-0 - retired
Carla Suarez (ESP) bt Klara Zakopalova (CZE x8) 6-4, 6-3
Kiki Bertens (NED) bt Dominika Cibulkova (SVK x4) 7-5, 6-4
Lucie Safarova (CZE x6) bt Alize Cornet (FRA) 6-2, 4-6, 6-2
Kristina Mladenovic (FRA) bt Yanina Wickmayer (BEL) 6-4, 6-4