AP

WUHAN, China (AP) — Daria Kasatkina recorded her first victory over Lesia Tsurenko in three attempts in the first round of the Wuhan Open on Sunday as US Open champion Naomi Osaka was forced to pull out of the tournament due to a viral illness.

Kasatkina, the No. 13 seeded Russian, defeated her Ukrainian opponent 6-4, 7-5 to set up a second round match against either Bernarda Pera or the US Open junior champion and qualifier Wang Xiyu.

No. 7-ranked Osaka withdrew from the tournament after losing in the final of the Toray Pan Pacific Open in Tokyo on Sunday with lucky loser Polona Hercog replacing her in the main draw.

"I'm very sorry to have to withdraw from Wuhan. I look forward to playing in Wuhan next year," Osaka said in a statement.

Earlier this week, former top-ranked Victoria Azarenka also pulled out after she was forced to retire in the quarterfinals in Tokyo due to a viral illness.

In other first round matches, the Chinese duo of Zheng Saisai and Zhang Shuai won their first round matches.

Zhang stunned Australian Samantha Stosur 6-2, 6-2 while Zheng defeated American Danielle Collins after losing the first set 2-6, 6-4, 6-2.

Anastasia Pavlyuchenkova, Julia Goerges, Monica Puig, Katerina Siniakova and Aliaksandra Sasnovich also advanced to the second round.