South Africans Richard Sterne and Trevor Fisher stretched their lead to five shots Saturday after three rounds of the 1.3 million euros ($1.737 million) Joburg Open.
They held a three-stroke advantage through the championship at Royal Johannesburg and Kensington Golf Club, which is co-sanctioned by the European Tour and the local Sunshine Tour.
Playing together, each fired a third-round 68 to share first place on 196, with compatriots George Coetzee, tournament favourite Charl Schwartzel and Jaco van Zyl as well as Chilean Felipe Aguilar on 201, the nearest challengers.
American Peter Uihlein is alone on 202 and the group a shot further back, includes South Africans Thomas Aiken and Garth Mulroy, Tommy Fleetwood of England, David Drysale of Scotland and Lorenzo Gagli of Italy.
Mulroy and Aiken posted the best third rounds -- 65 and 66 respectively over the par-72, 6942-metre east course at the north-eastern Johannesburg golf club -- but bridging a seven-stroke gap on the leaders is asking a lot of the pair.
Sterne, runner-up to Scotland's Stephen Gallacher in the Dubai Desert Classic last weekend, had three birdies on the outward nine to make the turn one shot behind Fisher, who was four-under par over the first nine holes.
But Fisher had an inconsistent inward nine with three birdies and three bogeys while 2008 Joburg Open champion, Sterne, displayed greater stability with two birdies and a solitary bogey as they both finished deadlocked.