The Englishman entered the final day at Gary Player Country Club three shots behind long-time leader Sergio Garcia but an eagle on the second put him at the top of the leaderboard and set up an enthralling three-way battle between those two and local favourite Louis Oosthuizen.
The heavyweight trio went blow-for-blow on one of the most entertaining afternoons of the season, and it was former World Number One Westwood who birdied five of his last eight holes to get to 15 under to prevail over his Major Championship
winning rivals.
Westwood’s triumph is his third at Gary Player Country Club, after the Sunshine Tour’s Dimension Data Pro-Am in 2000 and this event in 2010 and 2011, before it joined the European Tour International Schedule.
The 45-year-old’s last victory came at the 2014 Maybank Malaysian Open and he was fighting back the tears after taking his tally to a remarkable 24 on the European Tour and 43 worldwide.
Spaniard Garcia signed for a 70 to finish at 12 under, one shot ahead of Oosthuizen, who closed with a 69. England’s Ross Fisher was next at eight under, a shot clear of
countryman Matt Wallace and China’s Li Haotong.
Li needed a win to keep his hopes of winning the Race to Dubai alive, but results in Sun City mean that it will be either Francesco Molinari or Tommy Fleetwood who will be crowned Europe’s Number One, after next week’s
season-ending DP World Tour Championship, Dubai.
Belgian Thomas Detry finished at six under, one clear of England’s Aaron Rai and two ahead of another Englishman in Chris
Paisley, and South African Darren Fichardt.