Though the margin of victory was two, it came down to a nervy finish on the 72nd hole where Oosthuizen hit his tee shot into a water hazard right of the fairway.
From there Oosthuizen layed up with his third shot. Meanwhile, playing partner Schwartzel - who was two behind- went for the par five putting surface in two and was lucky to avoid the greenside water hazard left of the green.
Odds in Schwartzel’s favour
It meant the odds of Schwartzel getting up and down for birdie and Oosthuizen making bogey were good. However, Schwartzel hit an average chip to 15 feet while Oosthuizen was left with a 30 footer for par and victory outright.
The 2010 Open Champion then made no mistake as he poured in the putt from long range to close the door on his rival and fellow LIV Golf teammate. Schwartzel then missed his birdie attempt to keep the two-shot margin intact.
“This is a tournament I really really wanted,” said Oosthuizen afterwards.
Earlier, the final round had resumed after bad weather forced the fourth round into a Monday finish. The final group has played seven holes in the fourth round on Sunday, with Schwartzel and Oosthuizen locked on 16-under.
Completing the final group was Christiaan Bezuidenhout in solo third on 14-under after a final round four-under 68.
England’s Marco Penge, Germany’s Matti Schmid and Darius van Driel of the Netherlands were tied for fourth on 10-under.