Home hope Kurumi Nara overcame third seed Yulia Putintseva 6-2 6-2 to secure a place in the quarter-final of the Japan Women's Open.
Putintseva had won all four of the pair's previous encounters, but Nara came out on top with a comfortable win inside one hour and 26 minutes in Tokyo.
Nara, the only Japanese remaining in the competition after top seed Misaki Doi was dumped out in the opening round by Aliaksandra Sasnovich and Naomi Osaka lost 6-3 6-2 to Shuai Zhang - now the highest seed left in the competition - on Thursday, will face Jana Cepelova in the last eight.
Sasnovich was unable to reach that stage herself, though, going down 6-3 6-1 to Alison Riske, while Viktorija Golubic required over two and a half hours to beat Magda Linette 6-2 6-7 (5-7) 6-3.
Golubic will face off against Christina McHale in the quarter-finals after the American defeated qualifier Rebecca Peterson 2-6 6-2 7-6 (7-4) in a gruelling three-set encounter of similar length.