World number one Victoria Azarenka withdrew half-an-hour before the start of her semi-final against Serena Williams at the Brisbane International.
Azarenka was advised not to play after receiving treatment for an infection on the big toe of her right foot.
The Belarussian - who will be defending her Australian Open title later in January - has lost 11 of her 12 career meetings with 15-time major champion Williams, including all five last year concluding with the US Open final.
Azarenka explained the infection has been developing for more than a week and came as a result of a "bad pedicure experience".
She had part of the toenail removed on Thursday and fully expects to be fit for the opening major of the year, which starts in Melbourne on January 14.
"It's been there for the last 10 days and it's been getting worse," she said. "I had to take action, which I did yesterday, and I didn't have enough time to recover.
"It's just something that I had to do to make sure that I can be fully recovered and ready for the Australian Open. It's a compromise I had to make.
"It's just very unfortunate timing, because I was really looking forward to playing. But I'm also quite happy I had two matches here already, which was kind of the point, to come here and get some matches."
Russia's Anastasia Pavlyuchenkova will face Williams in the final after she overcame Ukrainian lucky loser Lesia Tsurenko 4-6 6-1 6-2 in an error-strewn affair that does not bode well for Saturday.