Keys saved a match point before winning in a final set tie-break while Sabalenka saw off close friend Paula Badosa.
The American advanced to the final with a roller-coaster victory that was so intense she couldn't recall one very important point.
Madison Keys saved a match point and came back to upset No. 2 Iga Swiatek 5-7, 6-1, 7-6 (10-8) in a high-intensity, ...