World No.5 Jessica Pegula has withdrawn from the semi-finals of the Adelaide International with illness, two days out from the start of the Australian Open.
The second-highest ranked American woman was scheduled to play Russia's Daria Kasatkina on Friday night but didn't take to the court.
In a post on social media, the tournament said Pegula was suffering from a gastrointestinal illness.
Pegula, who has made the quarter-finals for the past three years at Melbourne Park, has drawn Canadian world No.182 Rebecca Marino in the first round.
The American's Adelaide withdrawal means world No.15 Kasatkina will get a shot at a seventh career title in Saturday's final.
She will face sixth seed Jelena Ostapenko, after the Latvian toppled Russia's Ekaterina Alexandrova 6-2 7-6 (7-3) having shrugged off leg pains that hampered her earlier in the week.
"Sometimes when I had to play more aggressively, the last few seasons I was not doing this well," Ostapenko said on court.
"Now I feel in deciding moments when I have to go for my shots and when I have to put pressure on the opponent, I'm doing it better.
"I'm just feeling good and really excited to be in the finals."
Kasatkina progressed to the semi-finals with a walkover against Germany's Laura Siegmund (leg injury) and has played just two matches in the tournament.