England's Danny Willett landed six birdies and the biggest win of his career as he claimed the $1.25 million first prize at the Nedbank Challenge following a faultless final round at Sun City.
Shane Lowry finished with a second successive 71, which left him two under and 11th overall.
Lowry landed eagles on the par-five second and 14th holes but undid some of that good work with a double bogey on the eighth.
It is a second European Tour victory for 27-year-old Willett, who showed no sign of nerves to produce a final round 66, the best score of the day, for a tournament total of 18 under par and a four-shot win over compatriot Ross Fisher.
Willett and Fisher were part of an English trio that also included overnight leader Luke Donald, celebrating his 37th birthday, as the only realistic winners on Sunday.
Fisher, the leader after the first round, ended his tournament with a 68, equalling the second-best round of the day, but three bogeys in the first 10 holes saw Donald slip to third as he carded 73 to finish 12 under.
