Alexandr Dolgopolov retired injured from the Kooyong exhibition tournament in Melbourne on Friday, handing Spain's Fernando Verdasco the title.
Dolgopolov, seeded 21st the Australian Open which begins Monday, lost the opening set 7-6 (3) before calling for medical staff because of a leg injury, then saying he could not continue.
The Ukrainian is scheduled to play Paolo Lorenzi of Italy in the first round of the Australian Open. It was not immediately known if the injury jeopardized his appearance at Melbourne Park.
In a final round-robin match at Kooyong, Richard Gasquet of France beat Kei Nishikori of Japan 7-6 (4), 7-6 (6).
Later Friday, Czech Fed Cup teammates Petra Kvitova and Karolina Pliskova were to face off in the Sydney International women's final.