The No. 3-ranked Westwood ended with a 15-under 273 total to stay clear of Robert Karlsson in second, despite a final-round charge from the Swede which closed Westwood’s commanding seven-shot overnight lead.

Westwood made just two birdies on the final day and dropped three strokes over the back nine, but his dominant performance on Saturday — when he shot a course-record 62 — set up victory and only the second back-to-back win at Sun City over the last decade.

A smiling Westwood threw his ball into the galleries on No. 18 after beating out Karlsson (68), who made seven birdies but dropped shots at Nos. 1, 8 and 16 at the Gary Player Country Club.

American Jason Dufner (69) tied for third with Graeme McDowell (70) on 11-under, while top-ranked Luke Donald was 10 shots off the pace in seventh, closing with a level-par 72 on his return from a five-week layoff after winning the US PGA Tour money list.

South Korea’s Kyung-tae Kim was alone in fifth on 8 under, with Masters champion Charl Schwartzel two shots behind him in sixth.

Westwood was the only player in the top seven of the 12-man field to be over par on Sunday after bogeys at Nos. 12, 17 and 18, but none of the chasers could take advantage of the Englishman’s subdued finish.

McDowell made an early run with five birdies going out. But the Northern Irishman also slipped up with drops at Nos. 5, 7 and 16 — and a double-bogey at No. 15 — to fade away.

Nedbank Challenge rookie Dufner birdied three of his first five holes and holed his approach for an eagle two at No. 11. But Dufner had back-to-back bogies to finish his front nine and a double on No. 15 where he matched McDowell’s slip at the par-4.

Karlsson had a glimpse of a dramatic turnaround when he holed a 25-foot birdie putt on No. 17 to go 13-under, and playing partner Westwood pulled his four-footer to bogey the par-4 and slip to 16 under and three ahead.

But even a bogey finish from Westwood and a 39 coming home was enough for a second Nedbank Challenge title. He collected $1.25 million and followed Jim Furyk, who was the last man to defend his Sun City title in 2006.

Donald had one birdie and one bogey and parred 16 holes to finish 5-under a week ahead of the season-ending Dubai World Championship, where the top-ranked Englishman faces a showdown with Rory McIlroy for the European Tour money list title.

Behind Donald, No. 4-ranked Martin Kaymer crashed to a final-round 76 to drop to 4-under for the tournament. England’s Simon Dyson (72) was ninth on 1-under and Denmark’s Anders Hansen was 10th on even par.

Italian Francesco Molinari lifted himself off last place with a 73 as British Open Darren Clarke slipped to the bottom of the field with a 6-over 78 to be 9 over par for the tournament