Johanna Konta retired injured against Elina Svitolina in the Brisbane International quarter-final less than two weeks before the Australian Open.
The British number one took the first set 6-1 but Ukrainian Svitolina edged a second-set tie-break to level before Konta called a timeout for treatment.
The 26-year-old was having difficulty with her right hip and retired when 3-2 down in the deciding set.
Svitolina will face defending champion Karolina Pliskova or Kaia Kanepi.
The 23-year-old reached the semi-finals last year and looks to have momentum going into the Australian Open, where the first round gets underway on 15 January.
“Hopefully Jo will recover quickly and we will see her back on court soon,” said Svitolina afterwards. “She played a really good match today and you can see she’s really playing well.”
World-number-nine Konta had not reached a quarter-final of an event since the Western & Southern Open in Cincinnati in August and looked to be in fine touch as she dominated Svitolina in the opening set.
Her withdrawal will prompt doubt ahead of the first Grand Slam of the year. Konta reached the semi-finals of the Australian Open in 2016 and the quarter-finals in 2017, where she was beaten by eventual champion Serena Williams.