Englishman Daniel Brown was joined at the top of the SDC Championship leaderboard by Connor Syme ahead of the final round after the Scot fired a third-round 67 to reach 11 under par.
Syme began the day five shots off Brown's overnight lead, but as those in the final groups struggled for consistency on another windy day in Eastern Cape, he shot seven birdies and two bogeys to earn a share of the lead as he goes in search of a maiden DP World Tour title.
Brown, meanwhile, went into the day with a three-shot cushion but saw his lead trimmed to one at the turn before three bogeys in the first four holes of his back nine dropped him back to eight under.
He staged a phenomenal fightback, though, producing back-to-back birdies at the 14th and 15th before finishing with a birdie at the last to sign for a level-par 72.
England's Andy Sullivan was part of a three-way tie for third on nine under after carding a sparkling 66 which contained two eagles and two birdies. South African Robin Williams and American James Nicholas were also two shots off the lead.
Brown stretched his three-shot advantage to four at the earliest opportunity on Saturday with a birdie at the first.
After back-to-back pars at the second and third, there was a two-shot swing on the par-three fourth as Brown dropped his first shot of the day and playing partner Williams made a birdie to cut the gap to two strokes, with a match play situation beginning to develop in the final group.
Williams closed to within one shot with another birdie at the fifth, before both men took advantage of the long sixth.
Brown surrendered the outright lead with his second bogey at the short seventh, with a par good enough to earn Williams a share of the lead.
But when Williams dropped a shot at the ninth, Brown went into the turn with a one-shot lead on 11 under.
Both players started the back nine with a bogey, with Nicholas joining Brown at the summit on ten under.
And a second successive bogey at the 11th saw Brown drop out of the lead altogether.
Having earlier made five birdies - including a hat-trick from the sixth - and two bogeys in his first 13 holes, Syme took over at the top with a tap-in birdie on the par-three 14th.
And even though Syme picked up another shot on his way in - at the 16th - as he set the target at 11 under, Brown and Williams both birdied the 14th and 15th to get within one shot of the lead.
Brown gave himself birdie tries at the 16th and 17th but was unable to convert from around ten feet on both occasions, before closing his round with an eight-foot birdie to join the lead.
Brown said: "It was a little bit stressful at times but I didn't play too dissimilar to the last couple of days, to be honest.
"There's an element of luck out there. Because it's so windy, you've got to pick the right moments to hit your shot.
"I still feel good and hopefully I'll have a good day tomorrow."
Syme, who has had three second-placed finishes on the DP World Tour but has still not tasted victory at this level, said: "I'm really pleased.
"I putted really nicely today. It's always tricky in that breeze to do that, judging your pace from distance and stuff like that.
"I was here last year as well so it was definitely one I'd earmarked to come back down to, to have another go at it this year.
"It's a really cool part of the world and I'm happy to be back."
