Scott Jamieson turned in 33 to join Victor Dubuisson at the top of the leaderboard on day three of the Nedbank Golf Challenge hosted by Gary Player.
Frenchman Dubuisson had held a two-shot lead overnight at the seventh Rolex Series event of the season but could only turn in level par, allowing Scotland's Jamieson to catch him at six under.
Two-time Major champion Martin Kaymer was then a shot back at Gary Player Country Club, one clear of home favourite Branden Grace and England's Tyrrell Hatton.
Hatton was in the penultimate group of the day and he got off to an excellent start, holing a right-to-lefter from 15 feet on the first to join the group at four under, where he was soon joined by Jamieson who made a birdie on the second.
Kaymer holed a long putt on the second for a birdie of his own but he would need more of those to catch Dubuisson who, after sending his tee-shot on the first well right, hit a stunning recovery with a restricted back-swing to five feet for an opening birdie.
Defending champion Alex Noren had failed to get up and down from a bunker on the first to drop a shot but his second into the second was right over the flag as he bounced back with an eagle.
Jamieson hit a smart tee-shot into the par three fourth and holed a 20-footer to get to five under and when Dubuisson missed the green on the third and failed to get up and down from the rough, the lead was down to one.
A second birdie of the day from Kaymer on the fifth had him briefly within two but Dubuisson hit an excellent tee-shot into the fourth to get back to seven under.
Hatton picked up another shot on the fifth and Jamieson played an excellent chip on the eighth to save par but was outdone by playing partner Kaymer. The German had bogeyed the seventh but chipped in from the side of the green on the next to get back to four under.
Noren had made five pars in a row but went a long way left off the tee at the tricky eighth and surrendered a double-bogey with Hatton then dropping a single shot on the same hole.
Jamieson had been quietly going about his business as he so often does and he took advantage of the par five ninth to move within one of the lead before a three-putt on the eighth from Dubuisson had him in a share.
The conditions had got the better of Grace on day two as he fired a 75 and when he bogeyed the fifth, it looked like he could already be too far back. But he does not have seven European Tour titles for no reason and made birdies on the sixth, eighth, tenth and 11th to fly up the leaderboard.
Kaymer was playing beautifully and he made the most of the par five tenth to get within a shot of the lead.
Darren Fichardt, Louis Oosthuizen, Haydn Porteous and Charl Schwartzel made up a quartet of South Africans at three under, a shot clear of Noren, David Drysdale, Ross Fisher, Matthieu Pavon and Lee Westwood.