Dawie van der Walt shot a four-under 66 to win the Nelson Mandela Championship by two shots, giving the tournament a South African victory in a week when the country bids farewell to its former president.
Van der Walt finished with a three-round total of 15-under 195 on Saturday as the sun eventually shone on the final day of the rain-shortened event.
It was his second European Tour victory.
England's Matthew Baldwin (68) and Spain's Jorge Campillo (68) were tied for second.
Even before the rain disrupted the first two days, organisers had brought the schedule forward a day to make sure the tournament did not run over into Sunday out of respect for the state funeral of Mandela.
"It's making you kind of part of history, winning it at this time when it's sad for everyone and everyone's mourning and tomorrow's the big day,'' Van der Walt said, wearing a black ribbon on his cap.
"It obviously means a lot and can be something that I can keep close to my heart forever.''
Van der Walt lifted a trophy that depicts an image of Mandela surrounded by children and also won a painting bearing the signature of South Africa's most famous figure.
The tournament donated money to one of Mandela's charities, a children's hospital that bears his name.
Englishman Daniel Brooks had held a three-shot lead after the second round in Durban, which was only completed earlier Saturday because of the weather delays, but struggled with five bogeys and a double bogey in his final-round 76.
Van der Walt, who was tied for second heading to the final 18 holes, made five birdies and an eagle to go with three bogeys on the Mount Edgecombe course.
Coming in, he recovered from his third bogey at No 11 by making eagle at No 12 and birdie at No 13.
The South African also caught a break on the par-five No 14 when a shot heading toward the rough bounced favorably for him.
Neither Baldwin nor Campillo could apply enough pressure in the final stretch, with Baldwin making just one birdie in his last 11 and Campillo crucially dropping a shot at No 15.
Campillo and Colin Nel on Friday became the first players to card 59s in a European Tour event, although their scores don't count as records because players were given preferred lies on the rain-soaked course.
France's Romain Wattel was alone in fourth on 12 under and South Africa's Oliver Bekker fifth on 11 under. American John Hahn finished in a four-way tie for sixth alongside four-time European Tour winner Branden Grace.