South Africa survived a brilliant all-round show by Zimbabwe captain Sikandar Raza to record a five-wicket win on Sunday, which means they remained unbeaten ahead of a semi-final against New Zealand on Wednesday.
After Zimbabwe scored 153-7 in New Delhi, South Africa survived an early wobble.
Dewald Brevis hit 42 off 18 balls as the 2024 runners-up reached 154-5 in 17.5 overs.
Raza earlier hit 73 and then took 3-29 with his off-spin for Zimbabwe, who had stunned Australia and co-hosts Sri Lanka in the group stage to reach the Super Eights.
Raza struck on the third ball of the South African chase to send back Quinton de Kock, caught behind for a duck.
Raza bowled skipper Aiden Markram for four in the next over. Ryan Rickelton was hit on the helmet by a bouncer from Brad Evans and took five minutes to recover. He then lifted Evans for two straight sixes in the next over before the bowler had him caught for 31. Brevis and David Miller, who hit 22, put on 50 before two more quick strikes from Zimbabwe. Blessing Muzarabani dismissed Miller, and Raza removed Brevis.
Tristan Stubbs (21) and George Linde (30) then put on an unbeaten 53 to steer their side to the target. After choosing to bat, Zimbabwe lost the in-form opener Brian Bennett, who hit an unbeaten 97 in the defeat by India, for 15.
Raza reached his fifty off 29 balls before falling to left-armer Kwena Maphaka, caught by Miller off a leading edge.
Clive Madande boosted the total with 26 not out off 20 balls at the end. Maphaka took 2-21 from his four overs and Corbin Bosch 2-40.