Booker had led since Friday, and his margin was four shots with 10 holes to go. But the 35-year-old US PGA Tour rookie had double-bogeys on the 10 th and 16th for a 77, including a 42 on the back nine.
Singh overcame another day of strong winds at the TPC at Heron Bay to finish at 11-under 277, while Payne Stewart closed with a 70 to take second place in the tournament for the fifth time. Booker tied for third at 280 with Paraguay's Carlos Franco, Doug Dunakey and Mark O'Meara, who had two bogeys coming in drop from contention.
Singh, who began the day five shots behind, eagled the par-5, 602-yard fourth, which played downwind. The US PGA champion also made three birdies and two bogeys.
Winds gusting at more than 25 mph sent scores soaring, especially among the final threesome. Tommy Tolles and Bradley Hughes, paired with Booker, faded badly. Tolles finished with 77 for 282, and Hughes shot 80 for 285.
Singh sank a curling 25-foot birdie putt on 15 to close to within two strokes. He took the lead when Booker chunked a fairway iron into a bunker on the par-5 16th, laid up and three-putted from the fringe for a seven. That dropped Booker one shot behind Singh, who was playing two groups ahead on the final hole, which he parred.
In Malaga, Miguel Angel Jimenez, rode his luck yesterday to retain his Turespana Masters title by four strokes on the course where he learned the game. The 35-year-old twice pitched in from bunkers and had his ball kept out of the water by a spectator's legs in securing his fifth European Tour title.