Dean Burmester started the day three shots off the lead and carded a flawless 64 to win his third DP World Tour title at the Joburg Open by three shots.
"I actually can't describe what's really happened.
"The fans are always fantastic at home in South Africa and I'm so happy to be home and playing at home and eating a bit of braai meat and having a good time.
"Thriston is an amazing competitor and he had a three-shot lead so I knew I had to do something special and fortunately I was able to do that."
Darren Fichardt, who just regained his Tour card at the Qualifying School, carded his own bogey-free 64, featuring an eagle at the par-4 third hole that placed him in second place at 15-under.
England's Dan Bradbury, the only non-South African in the top-5, also closed with a 64 that included an eagle at the par-4 11th as well as two bogeys to finish third at 13-under.
Jacques Kruyswijk (69) and Zander Lombard (68) tied for fourth at 12-under.
Overnight leader Thriston Lawrence carded a 75 due to two double bogeys at the par-4s 2nd and 15th, three bogeys and two birdies, to finish 7th at 10-under.
The Joburg Open was the first event in the Open Qualifying Series and Burmester, Fichardt and Bradbury have all now qualified for The 152nd Open at Royal Troon.