Japan's Misaki Doi got the better of her veteran compatriot Kimiko Date-Krumm for the second time in two weeks at the Japan Open.
Doi, 21 years Date-Krumm's junior, came through 7-6 (7/3) 6-4 in match featuring just one service break, that coming in the ninth game of the second set.
Her reward is a quarter-final against third seed Samantha Stosur of Australia.
Also on Thursday, sixth seed Madison Keys saw off China's Zhang Shuai 6-4 6-0 in their second-round match.
And Zheng Jie of China claimed the scalp of ninth seed Kristina Mladenovic 6-7 (5/7) 6-2 6-0.