The second-seeded Radwanska, the younger sister of No. 3-ranked Agnieszka Radwanska, rallied from 5-1 down in the second set to defeat Maria-Teresa Torro-Flor of Spain 6-4, 7-5.
Third-seeded Alize Cornet of France stopped Nina Bratchikova of Russia 6-1, 6-3. Seventh-seeded Alexandra Panova of Russia beat Jarmila Gajdosova of Australia 4-6, 6-2, 7-5.
Spain's Lara Arruabarrena-Vecino defeated Slovakia's Jana Cepelova 6-1, 6-2. Sabina Sharipova downed Vlada Ekshibarova 6-4, 7-5 in a match between wild cards from Uzbekistan.