Elina Svitolina reached the Brisbane International semi-finals after Johanna Konta retired with a hip injury during the third set of their quarter-final on Thursday.
Ukraine's Svitolina was leading 1-6 7-6(6) 3-2 when Konta quit, raising doubts about the Briton's participation in the Australian Open which starts on Jan. 15.
World number nine Konta easily claimed the first set but from then on she lost momentum. She called for an injury timeout to treat her right hip ahead of the decider but was unable to continue despite holding serve for two games.
"I don't feel too comfortable saying really too much because, actually, I don't know yet until tomorrow morning," Konta said. "Hopefully it's nothing more than a low-grade strain and more muscle spasm more than anything."
Third seed Svitolina next plays Karolina Pliskova after the Czech defending champion ended the run of 2012 winner Kaia Kanepi 3-6 7-5 6-2.
Aliaksandra Sasnovich came from behind to dump out France's Alize Cornet 3-6 6-2 6-3 and takes on Anastasija Sevastova after the Latvian eased past Aleksandra Krunic 6-2 6-4 in the other quarter-final.