'I couldn't have asked for anything better,' said Druian. 'I was so calm.'
Michiel Bothma, who captured this event last year, joined Desvonde Botes and Mark Murless in a tie for second at 16-under-par 272. Overnight leader Craig Lile was one shot further back alone with Darren Fichardt and Dion Fourie at 15-under-par 273.
Druian began the day one shot behind Lile at Woodhill Country Club and made his move with four birdies on the front nine to reach 19 under.
'I just wanted to get a good start,' said Druian. 'The first four holes into the wind were quite tough, so it was good to come through those with pars. Then I made a 15-footer for birdie at the fifth and from there on I felt really calm. I believed then I was capable of winning.'
The 34-year-old continued to build his advantage with a birdie at the 11th before dropping a shot with a bogey at the 14th.
Druian got back to form with a birdie at the very next hole and capped his comeback win with a birdie at the 17th for his first title since the 1997 Royal Swazi Sun Open.
Lile, a good friend of Druian's, was unlucky on Sunday with a lone bogey at the eighth for a round of 73.
'At the start of the round we said to each other that if we were going to finish second, we'd do so to each other any day,' said Druian.
Louis Oosthuizen and Garth Mulroy shared eighth place at 14-under-par 274 while Tyrol Auret and Paul Eales finished in a tie for 10th at 12-under-par 276.
Jean Hugo, Cody Freeman and Shaun Norris came in one shot further back at 11- under-par 277.