Kvitova had won her first four encounters against Barty but the Queenslander turned the tables to win four in a row, including taking revenge in the quarter-finals at Melbourne Park last month.
Having exchanged breaks in the first three games of the semi-final, Kvitova settled down to build a 3-1 lead before fending off a couple of break points to claim the opening set.
Barty roared back in the second set, dropping just four points on her first serve and converting two break points to force a decider.
Despite conceding an early break, 2018 Doha champion Kvitova held her nerve to record her sixth career victory over an opponent ranked world No.1 as she reached her 37th WTA career final.
“It’s been a very positive week, it really has, and tonight was no different. It was an exceptional match. Obviously you look at a match and you debrief it to the nth degree, but I think another really great contest with Petra,” Barty said.
“I love testing myself against her and [it was] a match in where she played extremely well and took the match away from me in key moments.”
Earlier, Belarussian Sabalenka advanced to the 10th WTA final of her career with an impressive 6-4 6-3 victory over former world No.2 Svetlana Kuznetsova.
Sabalenka attacked Russian Kuznetsova’s serve with power and precision to earn three breaks in the opening set.
The ninth seed pressed home her advantage by winning the opening three games of the second set before serving out the match with a blistering forehand winner.
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