Fourth seed Roberta Vinci and former champion Jelena Jankovic secured berths in Friday's quarterfinals at the Wimbledon tune-up event in Birmingham.
The Italian Vinci held off Brit Heather Watson 6-3, 4-6, 6-1, while a fifth- seeded Jankovic advanced via walkover when Aussie Casey Dellacqua pulled out of their scheduled third-round match, citing an illness, at Edgbaston Priory Club.
The Serbian former world No. 1 Jankovic titled here in 2007 and was the runner-up in 2005.
In other action involving seeds, No. 8 Russian Ekaterina Makarova overcame ninth-seeded Marina Erakovic of New Zealand 2-6, 6-1, 6-3 and No. 13 Su-Wei Hsieh of Taiwan whipped Hungarian Melinda Czink 6-1, 6-2.
In other third-round play, American qualifier Melanie Oudin drubbed Russian Elena Vesnina 6-0, 6-2, American Irina Falconi topped Pole Urszula Radwanska 7-5, 6-3, and Chinese qualifier Zheng Jie doused Czech Andrea Hlavackova 6-4, 6-1.
Japan's Misaki Doi was leading Frenchwoman Stephanie Foretz Gacon 6-4, 2-2 when played was called because of rain on Thursday.
Three quarterfinals matches have been set, as Vinci will face Zheng, Makarova will battle Hsieh and Oudin will tackle her fellow American Falconi on Friday.
The winner of the $220,000 Aegon Classic will collect $37,000.