The 2019 US Open champion Bianca Andreescu's second comeback tournament ended in an agonising semi-final defeat in the Phillip Island Trophy in Melbourne on Thursday.
Andreescu held two match points in the third set against Marie Bouzkova but failed to convert as her Czech opponent completed a hard-fought 6-7 (9/11), 6-2, 7-5 victory.
Andreescu led 4-2 in the final set before world number 50 Bouzkova broke back in the seventh game.
Andreescu forced two match points as Bouzkova served at 4-5, but the Canadian twice found the net with volleys.
Bouzkova then broke again to go 6-5 ahead before serving out for the match.
World number nine Andreescu was knocked out of the Australian Open in the second round last week by Hsieh Su-wei in the Canadian's first tournament after returning from a 15-month injury absence.
The 20-year-old then entered the new WTA Tour event for early losers at the Australian Open and managed to get within two match wins of a fourth tour-level title after winning at Indian Wells, Toronto and the US Open in 2019.
Bouzkova will face Russian Daria Kasatkina in Friday's final of the WTA Tour 250 event.