Australian Adam Scott birdied the 18th to defeat South Africa's Ernie Els in a three-hole play-off and retain his Singapore Open title after torrential rain had reduced the tournament to 54 holes.

The pair had reached the ninth hole locked at 10-under par for the tournament but a tropical downpour forced the players off the course for a second time and the organisers opted to scrap the final round rather than return for a fifth day.

After three rounds, Els and Scott led the $3 million Asian Tour event on eight-under-par 205, three ahead of Australia's Brad Kennedy with China's Liang Wen-chong a further stroke adrift in fourth.

India's Shiv Kapur rounded off the top five after finishing his third round on two-under- par.

Following lengthy discussions, tournament organisers and the Asian Tour felt a three-hole play-off was the most suitable conclusion for the region's richest national open.

Matching pars on the 16th and 17th, Scott took control with a perfect tee shot on the par-five last while Els found the deep rough to the right of the fairway.

Els dragged his second out to the fairway and left his approach 30 feet from the pin, while Scott found the rough to the right of the green.

The Australian fired to within six feet with his third shot and when Els three-putted for bogey, Scott calmly slotted in his birdie to register a 11th career victory.

A record crowd of more than 6,000 were denied what was turning into a classic contest by the poor weather after the 26-year-old Australian had made the first move of the final round.

Searching for a first victory since his triumph here 12 months ago, the world number six surged three clear of his playing partner with consecutive birdies from the second hole as Els registered a bogey five on the third.

Els, also looking to end a long victory drought dating back to last December, battled back with birdies on the fourth and sixth, a hole where Scott drained a clutch par putt to stay one clear at the top of the leaderboard.

His advantage did not last much longer.

The 36-year-old Els chipped in from 37 yards for an eagle to leapfrog Scott, who could only manage a par.

The rain was getting heavier and with the suspension looming, Scott parred the par-three eighth - his 26th consecutive hole without dropping a shot - while Els paid for a poor tee shot into the left rough with the second bogey of his round.