Radwanska got by seventh-seeded Alexandra Panova 5-7, 6-2, 7-6 (7-3) in a match that lasted more than 3 hours. Both players suffered three breaks in the third set when neither managed to win even half the points on serve.
Radwanska eked out the win by taking the tiebreaker after the seesaw third set. Panova fought off four of five break points in taking the first set but Radwanska dropped just seven points on serve in winning the second.
Radwanska draws Irina-Camelia Begu in the semifinals. Begu outlasted eighth-seeded Galina Voskoboeva 3-6, 7-6 (7-1), 7-5 by finishing off all three of her break opportunities in the second and third sets.
Eva Birnerova ousted fifth-seeded Alexandra Cadantu 6-3, 4-6, 6-2 behind seven breaks and qualifier Donna Vekic finished off a 6-4, 6-4 win over No. 6-seeded Bojana Jovanovski with a pair of breaks in each set. Birnerova and Vekic also meet in the semifinals Friday.