Wickmayer defeated Chan Chin-Wei 7-6 (7-3), 6-4 while winning about three-quarters of the points on serve. She did drop her serve twice but went 3-for-3 in converting break-point chances.
Anna-Lena Friedsam eliminated fifth-seeded Kurumi Nara 6-3, 7-5 with five breaks and Anna Schmiedlova got by No. 6-seeded Caroline Garcia 6-7 (3-7), 6-1, 7-5, losing just 18 points in 16 games serving.
Three Taiwanese players were among those losing Tuesday. Luksika Kumkhum took out Lee Ya-Hsuan 6-0, 6-3 while qualifier Ekaterina Bychkova came away a 6-1, 7-5 winner over Chan Yung-Jan and Zheng Saisai beat Chan Hao-Ching 6-3, 6-1. The Chans are sisters.
Also Tuesday, Petra Martic defeated Lesley Kerkhove 6-2, 6-4 and Olga Govortsova topped Wang Qiang 6-4, 5-7, 7-5 in a match that took nearly 2 1/2 hours.