Top seed Naomi Osaka advanced to the quarterfinals of the Pan Pacific Open after defeating Bulgarian Viktoriya Tomova 7-5, 6-3.
Osaka, who suffered a pair of service breaks early in the game, is looking to win her first title in her native Japan after finishing runner-up in 2016 and 2018.
Her rival on duty will come out of the winner of the match between Kazakh Yulia Putintseva and Russian Varvara Flink.
Also on Wednesday, German fourth-seeded Angelique Kerber won her first match since Wimbledon, winning 6-2, 6-4 over American Nicole Gibbs.
Kerber will see them in the quarterfinals against Madison Keys of the United States, who eliminated Zarina Diyas 5-7, 6-0, 6-4.
Belgian Elise Mertens also advanced after defeating Taiwanese Hsieh Su-Wei 6-3, 1-6, 6-2.
At the Korean Open in Seoul, Russia’s Ekaterina Alexandrova (2) recovered to beat Czech Kristyna Pliskova 3-6, 6-3, 6-4 and reach the quarterfinals.
Alexandrova will have Kristie Ahn as her next opponent. The American beat Romanian Ana Bogdan 0-6, 6-4, 7-6 (2). AP