Scott Jamieson of Scotland surged into a five shot lead with a four under 68 after the third round of the Volvo Golf Champions European Tour event at Durban Country Club on Saturday.
Jamieson is on 15 under going into the final round, ahead of the trio of Louis Oosthuizen, Julien Quesne of France and Thai Thongchai Jaidee on 10 under.
Oosthuizen held a one stroke lead overnight, but faltered with a front nine four over par 40 as Jamieson moved ahead.
Jamieson won the rain-shortened Nelson Mandela Championship at Royal Durban Golf Club in December and would be looking for the elusive 'Durban double'.
"I said to a few people after the win, I was very grateful to get to a playoff, that experience I got from that under extreme pressure with a European tour title on the line was great," said Jamieson after his round.
Despite a bogey on his first hole, the Scot came back with a birdie on the par three second. To cap his nine off, as the rain started to come down, he eagled the par five eighth to get his round going.
"It was a bit of a slow start, so it was great to hit a three-iron to five feet on eight. So that really got me going," said Jamieson.
Three birdies in a row followed from the 11th. On the 439 metre par four 11th Jamieson came up short of the putting surface with his approach. However, a perfectly executed chip followed as the ball disappeared into the hole for a birdie.
On the par three 12th a good tee shot meant another birdie after a good putt.
On the short par four 13th hole, Jamieson hit a big drive but missed the green right. From a difficult spot in the rough he played another good chip to setup his third birdie on the trot.
"Even just a par save there [on 11] would have kept my momentum going, which is something I've been able to do throughout this whole week.
"When things haven't been quite going my way I've been able to hit a good chip or hole a putt.
"At 11 there I was possibly looking at bogey and I was able to chip in for birdie and that was perhaps a bit of a steal."
His second bogey of the day followed on 17 after a poor second shot from the middle of the fairway.
Jamieson came straight back with a birdie on the short par four 18th with a good chip to setup a tap-in birdie.