"It has been a long time coming. I'm over the moon that I can tick this off," said Horne. "I would've been disappointed to have played in South Africa for so long and never won a big tournament. And this is a big one. It's been going for many years with so many big names on the trophy. I really feel like I'm a big player in South Africa now."
Horne finished at 19-under 269 and won by three strokes over Jaco Ahlers (66), Alex Haindl (70) and Darren Fichardt (70) at Country Club Johannesburg.
Ulrich van den Berg (67), James Kamte (70) and Trevor Fisher, Jr. (70) tied for fifth at minus-15.