Serb Olga Danilovic, the No 6 seed, moved into the quarter-finals of the Osaka Open by winning against American Ashlyn Krueger 6-4, 6-4 at the Utsubo Tennis Center on Wednesday.
Danilovic, ranked No 42, will face the winner of the match between Belgian Elise Mertens, the No 3 seed, and Czech qualifier Tereza Valentova next.
Ahead of her victory, the Serb beat Japanese wildcard Nao Hibino (6-4, 1-6, 6-2).
Osaka WTA 250, other second-round results (Utsubo Tennis Center, hard, USD 275.094, most recent results first):
Marie Bouzkova vs. Viktorija Golubic
Dalma Galfi vs. Leylah Fernandez
Ann Li vs. Rebecca Sramkova
Elise Mertens vs. Tereza Valentova
Sorana Cirstea vs. Katie Boulter
Naomi Osaka vs. Suzan Lamens: wednesday
Jaqueline Cristian beat Jessica Bouzas Maneiro (8): 0-6, 6-4, 6-2