South African Branden Grace gave the chasing pack little to no chance of catching him on the second day of the Alfred Dunhill Championship as he stretched his lead to five strokes.
The 26-year-old clearly likes home soil, having won this event and the Joburg Open in 2012.
Starting the day at Leopard Creek Country Club three ahead a 66, marred only by a bogey on the short fifth, saw him extend his cushion further as Italian Francesco Molinari was the only player to better his score, by one, and moved into second place on 11 under as a result.
Kevin Phelan was the only Irish player to make the cut, finishing on one under par, after a 71 that included four birdies and three bogeys.
Damien McGrane's 73 left him level par and one short of qualifying for the weekend.
Peter Lawrie dropped six shots, including a double-bogey and a bogey, in his final three holes for a six-over 78.