Dinara Safina caused the first upset at the Open Gaz de France in Paris with a 6-4 6-2 win over sixth-seed Karolina Sprem of Croatia.
Safina, the sister of two-time Grand Slam winner Marat Safin, next plays fellow Russian Vera Douchevina.
Seventh seed Silvia Farina Elia registered an impressive 6-0 6-0 defeat of Klara Koukalova of the Czech Republic.
Second seed Amelie Mauresmo will play fellow Frenchwoman Mary Pierce.
Former French Open champion Pierce beat Spain's Anabel Medina Garrigues 6-1 6-2.