Gerald Coetzee took 4-19 in four overs as SA A restricted the hosts to 135-9 in their 20 overs.
Milton Shumba and Ryan Burl both made 41 for the Zimbabwe XI.
However, SA A then produced their worst batting display of the series, being bowled out for 73 in 16 overs.
#4thT20 | After 5 overs, 🇿🇦 A are 24-3
(Khaya Zondo 2*, Heinrich Klaasen 1*), need 112 runs in 90 balls
Live streaming 👉 https://t.co/XriQe2mJeC#ZIMXIvSAA | #VisitZimbabwe pic.twitter.com/fJRjmw8pri
— Zimbabwe Cricket (@ZimCricketv) May 8, 2022
Only Khaya Zondo (18) and captain Heinrich Klaasen (14) reached double figures.
Shumba (4-15) and Sikandar Raza (3-18) did the bulk of the damage with the ball.
SA A will take a 3-1 lead into the fifth and final match of the series at the same venue on Tuesday.
