Naomi Osaka retired during her second-round match Wednesday at the Nature Valley Classic in Birmingham, England, due to abdominal issues.

Osaka, ranked 18th in the world, withdrew from her match against Dalia Jakupovic after the No. 113 Slovenian had taken the first set 6-3.

After a brief visit from her trainer, the 20-year-old retired citing abdominal trouble, the organizers said. Osaka also made a second-round exit at this grass-court tournament last year.

She is scheduled to compete at next week's Nature Valley International in Eastbourne, England. The WTA Premier level tournament is a warmup event for Wimbledon, which starts July 2 in London.