Coco Gauff overpowered Karolina Muchova in straight sets to win the China Open on Sunday for her second title of the year and eighth overall.
World number two Sabalenka was on a streak of 15 victories in a row, claiming titles in Cincinnati and then the US Open for the first time.
The sixth-ranked American came through 1-6, 6-4, 6-2 and will take on world number two and Australian Open champion Aryna Sabalenka in Saturday's championship match.
Osaka has been unable to build momentum in her comeback, and her first round win over Jelena Ostapenko was her first in four years over a top-10 player.
Coco Gauff vs Aryna Sabalenka Highlights: Coco Gauff claimed her first Grand Slam title.
American teenager Coco Gauff defeated Czech Republic's Karolina Muchova to qualify for her maiden US Open Women's Singles final.
Coco Gauff captured the biggest title of her career on Sunday, powering past Karolina Muchova 6-3, 6-4 to win the WTA Cincinnati Open.
Iga Swiatek, unfazed by two lengthy rain delays, held off Karolina Muchova 6-1, 4-6, 6-4 to reach the quarter-finals of the WTA Montreal Open on Thursday
Iga Swiatek came through 6-2, 5-7, 6-4 to become the first woman since Justine Henin in 2007 to win back-to-back French Opens.
French Open 2023 Final, Swiatek vs Muchova Highlights: Iga Swiatek claimed the French Open 2023 title by defeating Karolina Muchova.