Ons Jabeur of Tunisia. AFP
Spanish second seed Muguruza advanced to Sunday's championship match by walkover when Czech Marketa Vondrousova, the Tokyo Olympic runner-up, pulled out due to injury.
Sixth-seed Jabeur, ranked a career-high 16th, defeated Kazakhstan's fifth-seeded Elena Rybakina 6-4, 3-2 when 17th-ranked Rybakina retired.
Ninth-ranked Muguruza, seeking her second title of the year, is also chasing a berth in the eight-player WTA Finals. Muguruza won her eighth career WTA crown in March at Dubai.
Jabeur, who ousted top seed Elina Svitolina in the quarter-finals, won her only WTA title in June at Birmingham.
Muguruza and Jabeur have split two prior career matchups.
Jabeur beat Muguruza in the third round at Wimbledon earlier this year. Muguruza edged Jabeur in a third-set tie-break last year at Hobart.
Jabeur improved to 2-1 against Rybakina, winning their most recent prior meeting in March at Dubai.
Rybakina, who was fourth at Tokyo, missed a chance for her third WTA title after trophies at Hobart last year and Bucharest in 2019.
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