Kontaveit, ranked 27th, advanced from the other semifinal after local favorite Qiang Wang was forced to retire with a thigh injury, trailing 6-2, 2-1 at the time.
Sabalenka, who earned her maiden WTA title at this summer's Connecticut Open, faces Estonia's Anett Kontaveit in the final.
The promising 20-year-old also won 84 per cent of points on her first serve, coming from a break down in the first set and refusing to allow Barty a way back after taking a 2-0 lead in the second.
She's risen from No.73 in the world to No.20 this year.
Kvitova is the most successful player in Wuhan's short history after winning in 2014 and 2016, but she will have to wait for a third crown after Pavlyuchenkova came from a set down to secure a 3-6 6-3 6-3 win.
"Everything was going according to plan, I was playing great tennis", De Minaur told ATPWorldTour.com.
John Millman will wait to see if there is one more withdrawal from next week's ATP Tokyo main draw for him to make it before he commits to a flight from Brisbane. "She's an absolute quality player".
Sabalenka, looking for the second WTA title of her career after clinching the Connecticut Open in August, grew even stronger in the second set as her aggressive and accurate shots often left the 17th-ranked Barty flat-footed.
"In terms of technique, in the past year I think I've been doing quite similar (things) but I'm really more confident", said Wang, whose family paid for her to train in Japan during her formative years, instead of sticking with China's state-run sports system.
The Australian is through to the last four for a second successive year, though she had to come back from a break down in the decider to finally get the better of Russian Pavlyuchenkova.
Barty goes on to face No. 28 Anastasia Pavlyuchenkova, who stunned world No. 5 Petra Kvitova 3-6, 6-3, 6-3 in the following match on center court today.
In the doubles, Shuko Aoyama and Lidziya Marozava beat Timea Babos and Kristina Mladenovic 6-2, 7-5.