Schwartzel found a greenside bunker on No. 14, three-putted on No. 16 for double-bogey and fluffed a tee shot on 17 to drop another shot. He also found the rough off the tee on No. 18 and had to scramble for a par to send the tournament to a playoff.
Both drove into the long grass when they teed off at No. 18 again. But Sullivan recovered with a sublime low punch through the tree branches and to 12 feet, before rolling in the putt for his maiden tour title. He pumped his fist with delight after a missed birdie on the last in regulation play appeared to have ensured he would have no chance at victory.
Sullivan became just the second Englishman to win the South African Open " the second oldest tournament in professional golf " after Tommy Horton in 1970. His seven-shot comeback was the biggest in the final round since the event joined the European Tour in 1997.
Lee Slattery was third on 10 under. Ernie Els, who was in the mix after a first-round 67, finished with a 72 and in a tie for 20th.