Top-seeded Maria Kirilenko and reigning round winners at the hardcourt Guangzhou International tennis event.
The Russian Kirilenko whipped France's Iryna Bremond 6-3, 6-1, while the second-seeded Gajdosova continued her winning ways in Guangzhou with a 4-6, 6-2, 6-3 come-from-behind victory over Luxembourg's Mandy Minella on Day 3 at Tianhe Sports Centre.
The 28th-ranked Kirilenko will now appear in only her second quarterfinal of the year, while the world No. 34 Gajdosova will compete in her fifth.
Kirilenko's quarterfinal opponent on Thursday will be little-known Ukrainian Tetiana Luzhanska, while the Australian Gajdosova will encounter eighth-seeded Slovak Magdalena Rybarikova.
Three other seeds landed in the round of eight, as No. 4 Croat Petra Martic overcame Kazakhstani qualifier Zarina Diyas 4-6, 6-2, 6-4, No. 7 South African Chanelle Scheepers came back to best qualifier Su-Wei Hsieh of Taipei 3-6, 7-6 (7-1), 6-1, and Rybarikova downed France's Aravane Rezai 6-4, 6-1.
The other quarterfinals will pit Martic against Chinese crowd favorite Zheng Jie and Scheepers versus Poland's Urszula Radwanska. Zheng defeated Thai Noppawan Lertcheewakarn 6-3, 7-5, while Radwanska fought back to beat China's Yung-Jan Chan 2-6, 6-2, 6-2.
One other second-rounder saw the aforementioned Luzhanska outlast Chinese qualifier Yi-Jin Zhao 6-4, 2-6, 7-5.
The 2011 Guangzhou titlist will collect $37,000.