Brandon Stone edged closer to a second European Tour title with a second consecutive six-under 66 in the third round of the Alfred Dunhill Championship on Saturday to lead by three shots at Leopard Creek Country Club.
The 23-year-old South African moved to 17-under-par for the tournament, ahead of compatriots Keith Horne (67) and Charl Schwartzel (68), and England's Chris Hanson (68), who were tied second on 14-under.
Stone is looking to add to his BMW Open title won in January.
He extended a one-shot overnight lead after birdies in four of his first six holes and had a rollercoaster run at the start of his back nine with three more birdies and a bogey on the par-three 12th.
He was less aggressive after that, completing his round with five pars as the chasing pack failed to narrow his three-shot lead.
One of those was Schwartzel, who is still in contention to join Bernhard Langer, Tom Watson and Tiger Woods as the only players to win the same European Tour event five times.
Schwartzel turned at level par for the day, but then hit a hot-streak with five birdies in his first six holes of the back nine, before his charge was halted by a bogey on the par-three 16th.
The low round of the tournament was carded by Scotland's David Drysdale, who sank eight birdies in a faultless 64 to stay just in contention on 11-under-par.
Sunday's final round will have an early start with extreme heat and thunderstorms predicted for the afternoon.
