The unseeded Muchova beat the world number two 7-6 (7/5), 2-6, 6-4 in Beijing and said: "Tennis is a roller-coaster."
In another topsy-turvy quarter-final, home hero Zheng fought back to defeat Mirra Andreeva 5-7, 6-0, 6-4, with the 17-year-old Russian reduced to tears in the third set.
Last year's US Open champion Coco Gauff plays Spain's former world number two Paula Badosa in the other semi-final.
Sabalenka's streak of victories saw her claim titles in Cincinnati and then the US Open for the first time. Читать дальше...