South Africans Darren Fichardt and Jaco Van Zyl took over at the top of the Africa Open leaderboard midway through a fascinating third round.
With low scoring the order of the day, Adilson Da Silva saw his three shot overnight advantage disappear as the Brazilian covered the first eight holes in one over par.
That barely told the story, however. After two opening pars the 41 year old hit a splendid second to eight feet at the long third and holed the eagle putt to extend his lead to four shots.
Four straight pars followed, but a string of problems on the eighth cost the Sunshine Tour regular the lead.
Da Silva drove into a bunker, needed two shots to get out, duffed his fourth left into more sand at the side of the green then two-putted for a triple bogey seven.
At 13 under he was one behind Fichardt and playing partner Van Zyl.
Saint Omer Open winner Fichardt matched Da Silva’s eagle at the third and had four birdies in his first eight holes, while Van Zyl picked up three shots over the opening stretch.
Argentine Emiliano Grillo held the clubhouse lead on 11 under after a 64, and he was level in fourth place with England’s John Parry, France’s Gregory Bourdy and South African Oliver Bekker.
Things not get much better for Da Silva at the ninth – he missed the fairway with his tee shot, came up short of the green with his approach and failed to get up and down - turning in 39 as a result.
Fichardt bogeyed the same hole, leaving Van Zyl one ahead at the turn.