The 26-year-old home player carded a third consecutive 67 at the Gary Player Country Club in Sun City to sweep clear of the field on 15-under-par.
Bezuidenhout is now 18 holes away from becoming the first player since Justin Rose in 2017 to win successive events on the European Tour circuit after he won last week’s Alfred Dunhill Championship at Leopard Creek.
“I’m really happy to be in this position,” said Bezuidenhout, who is being chased by compatriot Dylan Frittelli (70) and Welshman Jamie Donaldson (72).
“I’ve played three solid rounds of golf and have stuck to my gameplan by not taking the golf course on and just keeping it in play.”
Scottish duo Connor Syme and Scott Jamieson are both inside the top 20 heading into the final circuit as they bid to seal spots in the season-ending DP World Tour Championship in Dubai next week.
Syme, who sits 68th in the Race to Dubai, carded five birdies in his 69, which left the Fifer sitting in a tie for 12th on five-under.
Jamieson, who started the week two spots higher in the standings, finished with four birdies for the same score, leaving him sharing 18th spot on three-under.
The 60-man field for next week’s finale is likely to go down to somewhere in the 70s on the Race to Dubai list, meaning both Syme and Jamieson are almost certain to get in.
Calum Hill (72) and David Law (73) are tied for 26th on one-under.