Aryna Sabalenka eliminated world number one Iga Swiatek 6-2 2-6 6-1 on Sunday to advance to the decider of the WTA Finals.
Swiatek had not lost a set during her week in Fort Worth entering the contest, earning her spot in the semi-final after straight-sets wins against Coco Gauff, Caroline Garcia and Daria Kasatkina.
Needing to start well to give herself a chance against the in-form Polish star, Sabalenka did just that, breaking Swiatek in her first service game.
Swiatek broke back instantly, but she had no response when the BelaruSsian secured two more breaks of serve in the opening frame to wrap it up in 40 minutes.
After winning only 43 per cent (12-of-28) of her service points in the first set, Swiatek seemed to figure things out in the second, raising that number to 61 per cent (17-of-28) to win the first four games and run away with it and send the match to a decider.
But Swiatek's uncharacteristic errors came back to bite her, committing two double faults in each of the three sets, and after posting a combined 21 winners with 17 unforced errors in the first two frames, she mustered only five winners with nine unforced errors in the last.
Sabalenka rattled off five consecutive games to close out the match, utilising her imposing serve to get the job done, serving 12 aces to Swiatek's one.
She will now face Caroline Garcia in the final after the Frenchwoman proved too strong for Maria Sakkari in a 6-3 6-2 victory earlier in the day.
Sabalenka - 12/9
Swiatek - 1/6
Sabalenka - 23/19
Swiatek - 26/26
BREAK POINTS WON
Sabalenka - 6/13
Swiatek - 4/10