World No.3 Halep had claimed straight-set wins over Ekaterina Alexandrova and Marketa Vondrousova en route to the semi-finals, but met her match in the form of Belarusian Sabalenka, who triumphed 6-3 6-2.
A nine-time singles champion, Sabalenka made it into a 14th career final without conceding a single break, as she managed to keep Romanian Halep at arm's length.
Standing between Sabalenka and a 10th singles title is world No.1 Barty who celebrated her 25th birthday by coming from behind to defeat Elina Svitolina 4-6 7-6 (7-5) 6-2.
