Sabalenka exacted sweet revenge over Coco Gauff to power into a second successive Open final with 7-6 (7-2) 6-4 victory on Thursday night before Zheng ended the inspired run of Ukrainian qualifier Dayana Yastremska with an equally impressive 6-4 6-4 win.
After losing last year's US Open title decider to Gauff at Flushing Meadows, Sabalenka turned the tables on the American teenager in a blockbuster semi-final at Rod Laver Arena.
Sabalenka is now a hot favourite to topple 12th-seeded Zheng on Saturday night and become the first player since her fellow Belarusian Victoria Azarenka in 2013 to successfully defend the women's title at Melbourne Park.
Looking almost unstoppable, the 25-year-old world No.2 has yet to drop a set this campaign and showed enormous resolve in not only snapping Gauff's 12-match grand slam winning streak but also the fourth seed's unbeaten start to 2024.
Aryna Sabalenka remains on track to win consecutive Australian Open singles titles. (Joel Carrett/AAP PHOTOS)
"I was just ready for anything tonight and I think that was the key - and definitely your support, guys," Sabalenka told the capacity crowd at RLA.
"Last time I played her (in New York), I didn't have, I would say, almost any support.
"I was able to focus on myself and I was prepared that she's going to move really good and she's going to put all balls back to me and I just have to be ready to play an extra shot."
Gauff won the season-opening WTA event in Auckland and had been hoping to become the first woman to capture back-to-back majors since Naomi Osaka completed the Australian Open-US Open double three years ago.
Instead, Sabalenka is now within a win of shedding her tag as a one-slam wonder after producing her best performance of the tournament.
Coco Gauff's loss to defending champion Aryna Sabalenka at Melbourne Park was her first of 2024. (Joel Carrett/AAP PHOTOS)
The second seed made a flying start, holding her first service game to love, while Gauff opened the night with two double-faults and was broken almost in the blink of an eye.
The American broke back to level at 2-2 only to drop three of the next four games to trail 5-3.
Sabalenka failed to serve it out, then missed a set point in the 10th game as Gauff roared to a 6-5 lead.
Alas, this time Gauff was unable to hold and paid the price as Sabalenka raised her game with a clutch tiebreaker to take an all-important one-set-to-love lead.
Six double-faults in the first set cruelled Gauff, but both players stepped up their serves in the second to slug it out with some fierce baseline rallies.
It was Sabalenka, though, who nabbed the only break of the set in the ninth game, before coolly closing out the match after one hour, 42 minutes.
Zheng Qinwen is hoping to follow Li Na in 2014 as China's second Australian Open singles champion. (Joel Carrett/AAP PHOTOS)
Zheng, the WTA's 2023 most improved player of the year, fittingly progressed to her maiden grand slam final on the 10th anniversary of compatriot Li Na's watershed Australian Open victory in 2013.
Li remains the only Asian woman to win a grand slam singles crown, but is in Melbourne hoping to see 21-year-old Zheng become the second.
"I'm super excited to have such a great performance today and arrive in the final," Zheng said after denying Yastremska the chance to join Britain's 2021 US Open champion Emma Raducanu as only the second qualifier in history to win a grand slam singles title.
"My opponent, she's playing unbelievable tennis and got really good baseline stroke.
"Oh, it's tough to explain my feeling now."
