ISTANBUL (AP) -- Tsvetana Pironkova of Bulgaria was the only seed - the No. 8 and last - to reach the Istanbul Cup quarterfinals on Thursday.

Pironkova defeated Kurumi Nara of Japan 6-3, 1-6, 6-1, then learned fourth-seeded Alize Cornet of France was overhauled by Kirsten Flipkens of Belgium, and fifth-seeded Camila Giorgi lost an all-Italian match with Francesca Schiavone.

Flipkens won 2-6, 6-1, 6-2, and Schiavone 6-4, 7-6 (6), for her first quarterfinal since February.

They meet in the quarters on Friday.

Ukrainian qualifier Kateryna Bondarenko, who ousted Venus Williams, beat Mona Barthel of Germany 6-3, 4-6, 6-2 in their second-round match.