Naomi Osaka’s fitness for the Australian Open is in question after the four-time Grand Slam champion and suffered an apparent abdominal injury Sunday.

The former world No. 1 and four-time Grand Slam champion retired from the final of the WTA Auckland Open, the last tune-up before the Australian Open, with an apparent medical issue on Sunday. She had been leading Denmark's Clara Tauson 6-4 before her exit left Tauson as the tournament's champion.

Osaka had won the first set of the final 6-4 against Denmark's Clara Tauson when she spoke to her coach Patrick Mouratoglou, the chair umpire, and a tour trainer before deciding to withdraw.