Former No. 1 Dinara Safina beat Alize Cornet of France 6-1, 6-3 to reach the quarterfinals of the Grand Prix SAR on Thursday.
The Russian improved her record against the eighth-seeded Cornet to 3-0.
Safina will play Russia's Anastasia Pivovarova in her second straight quarterfinal after reaching the last eight of the Andalucia Tennis Experience, where she retied after lower back pains.
Pivovarova upset second-seeded Yaroslava Shvedova of Kazakhstan 6-2, 7-6 (5), meaning both top seeds are out following Aravane Rezai's second-round exit on Wednesday.
Pivovarova double-faulted six times on her stuttering serve, but broke her opponent five times in the match.
Alberta Brianti of Italy also advanced to the last eight after beating Russia's Ksenia Pervak 7-5, 6-2. She will face Melanie Oudin of the United States, who advanced with a walkover win after Slovenia's Polona Hercog withdrew with a right ankle injury.