World number three Lee Westwood of England retained his Nedbank Golf Challenge title Sunday despite shooting a one-over-par 73 in the final round. A record third-round 62 helped him to a 15-under total of 273 -- two strokes less than it took Swede Robert Karlsson to cover four rounds over the 7162-metre Gary Player Country Club at this north-west entertainment resort. Karlsson holed a tricky final-green par putt for a 68, the best round of a day when he, Graeme McDowell of Northern Ireland and American Jason Dufner tried in vain to catch the Englishman who led by seven shots overnight. Westwood opted for a conservative approach and after turning in 34 with birdies at the sixth and ninth holes, spoilt his inward nine with bogeys at 12 and on the final two holes. \"Incredible! This is a special win and my mum and dad are here to see me do it,\" said Westwood after notching up the 36th victory of his professional golf career. \"I was seven shots ahead going into the final round but no lead is ever big enough. It was a difficult situation choosing between a conservative and an aggressive approach. \"Robert, Graeme and Jason came after me and made some early birdies -- but I never lost confidence in my ability to win this tournament. I love playing at Sun City.\" The 38-year-old became the sixth golfer after South Africans David Frost and Ernie Els, Zimbabwean Nick Price, American Jim Furyk and the late Seve Ballesteros of Spain to win back-to-back Nedbank Challenge titles. Dufner (69) and McDowell (70) shared third place on 277, South Korean Kim Kyung-Tae (70) finished on 280 and reigning US Masters champion Charl Schwartzel of South Africa (72) occupied sixth place nine shots adrift of Westwood. World number one Luke Donald of England failed once again to put together an eyecatching round, firing an even-par 72 to finish 10 shots behind the winner. German Martin Kaymer, ranked fourth in the world below Donald, Rory McIlroy of Northern Ireland and Westwood, had a woeful day as he slumped to a 76 amid numerous visits to the rough bordering tight fairways.