Thomas Aiken led by one as the leaders started the back nine during the third round of the Joburg Open on the East Course of the Royal Johannesburg & Kensington Golf Club.
The South African was a shot behind halfway leaders Charl Schwartzel, Garth Mulroy and Jamie Elson at the start, but all three dropped shots during their opening holes.
Defending champion Schwartzel, who recorded a thrilling 61 in round two, faltered on the par three second where he made a four, while compatriot Mulroy began with a five on the par four first.
Englishman Elson fared even worse on the first hole with a double bogey six, although he managed to pull back a shot with a birdie on the fourth hole.
The trio were playing together after the traditional two-ball play was abandoned in favour of three-balls on day three after a rain-affected day two mean that more than 25 players had to come back this morning to complete second rounds.
That meant a later tee-off with half of the 72-man field teeing off on the ninth hole.
And Aiken took full advantage of their slips to carve out a narrow lead, with a majestic third at the par five eighth - he had been bunkered off the tee - setting up a two foot birdie.
He reached 16 under with an 18 foot birdie at the tenth, to sit one ahead of Schwartzel, who recorded a hattrick of birdies approaching the turn.
Mulroy was in third having reached the turn one under on the day to be 14 under for the week.
That left Elson and compatriot Ben Evans in fourth on 13 under.
Challenge Tour regular Evans was making good progress after he picked up three birdies in his first six holes, and a 15 footer at the ninth helped him reach the turn in 32.
Elson completed the recovery from his early double bogey with a remarkable birdie at the par five eighth.
Deep in the trees off the tee, his misjudged second took a fortunate bounce off an advertising hoarding into light rough, before he hit a fantastic third to leave a simple five foot birdie putt.
Earlier this morning the cut was drawn at four under, meaning the likes of Darren Clarke and former champion Richard Sterne had just survived to play the weekend.