Branden Grace beat Ernie Els and Retief Goosen in a three-way South African play-off to seal the Volvo Golf Champions title.
Els put himself in contention with a final-round 67 to finish 12 under, with Grace missing a short putt on the 18th to win it over 72 holes.
But the 23-year-old made up for that by winning his second tournament in a row at the first play-off hole.
Scotland's Paul Lawrie and Ireland's Padraig Harrington finished joint 10th.
"I'm really ecstatic," said Grace. "It's been a great week and a dream come true winning an event like this in your home town."
Grace won his first European Tour title at the Joburg Open last week, having qualified for the European Tour via the 2011 Qualifying School last month.
He becomes the first player since Fred Couples in 1995 to follow his maiden European Tour victory with another win.
He also maintains his position at the top of the Race to Dubai standings - albeit after only three weeks - and moves into the world's top 100.
Of his missed putt on the last hole, Grace added: "I would have like to have finished it there and then.
"There was a little bit of nerves. Actually I hit quite a good putt but just misread it a bit.
"Now I can say I've beaten [Els and Goosen] in a play-off and that's something nice to say."
Els went round in six under par - the equal best of the day with England's Robert Rock - to set the clubhouse target, having eagled the 13th and almost chipped in for another at the last.
Goosen also eagled the 13th and birdied three of the last four holes in a round of 70.
Grace carded a 71, while Belgian Nicolas Colsaerts, who was tied for the lead with one hole to play, hit a wild drive en route to a bogey six that saw him slip to fourth.
Europe Ryder Cup captain Jose Maria Olazabal shared top spot after starting with two birdies, but slipped back to sixth, while Lawrie and Harrington shot rounds of 74 and 76 respectively.