Aryna Sabalenka toppled world number one Iga Swiatek 6-2, 2-6, 6-1 on Sunday to set up a title clash with Caroline Garcia at the season-ending WTA Finals.
Seventh-ranked Sabalenka avenged a three-set defeat to Poland's Swiatek in the semi-finals at the US Open, where Swiatek went on to capture her second Grand Slam title of the year after her victory at Roland Garros.
Sixth-ranked Garcia of France had powered past Greece's Maria Sakkari 6-3, 6-2 in the other semi-final.
Sabalenka, who called it a "miracle" that she qualified for the event after her mid-season struggles, fired 23 winners, including a dozen aces, with just 19 unforced errors.
Swiatek, whose remarkable season included eight singles titles, saw her 15-match winning streak against top 10 players end.
She had 26 winners and 26 unforced errors as her usually fearsome forehand was uncharacteristically unreliable.
Swiatek had been broken just once as she won all three of her round-robin matches, but was broken three times in the opening set Sunday as Sabalenka took charge.
Swiatek seemed to have re-set, however, racing to a 4-0 lead in the second before Sabalenka managed to fend off a break point to hold for 4-1. Although Sabalenka broke to cut the deficit to 4-2, Swiatek regained the break and swiftly served it out to knot the match at one set apiece.
As in their US Open clash, Sabalenka went up an early break in the third.
This time, however, she was able to make the advantage stand up, breaking again for a 5-1 lead and closing it out in impressive style with an ace and a service winner.
On Monday, Sabalenka and Garcia will renew a rivalry that has seen them split their four encounters 2-2.
Garcia, who has powered up the rankings with three titles this season, put on a clinic against Sakkari, wrapping up the win in 75 minutes.
She gained the decisive break in the first for a 4-2 lead and closed out the set with a love game, then powered to a 4-0 lead in the second.
Garcia's first double fault of the match gave Sakkari a break point in the sixth game, but Garcia responded with an ace and grabbed a 5-1 lead with a stinging backhand that kissed the sideline.
Sakkari held to force Garcia to serve it out, and she polished it off on her second match point when Sakkari sent a service return into the net.
Garcia, who could only kneel to catch her breath after a thrilling three-set win over Daria Kasatkina on Saturday to capture the last semi-final spot, had plenty of energy for a skipping, leaping celebration on the court at Dickies Arena in Fort Worth.
The event was moved to Texas due to continuing pandemic-related issues with the Chinese city of Shenzhen, which was initially due to host, as well as the WTA's dispute with China over the status of player Peng Shuai.