Sabbatini sank a 2-foot par putt on No. 18 to finish at 9-under 271. He earned his first PGA Tour title since the 2009 Byron Nelson Championship and sixth overall.
Y.E. Yang birdied the final hole for a closing 66 to finish 8 under. Jerry Kelly, who played with Sabbatini and Yang in the final threesome, shot a 67 and took third at 7 under.
Sabbatini started the final round ahead by five shots, and was still in front by five when he finished No. 8. But Yang was within one stroke seven holes later, thanks to birdies on Nos. 12 and 14 and two bogeys by Sabbatini.
Then came treacherous Nos. 15-17, the water-laden stretch known as the Bear Trap. But there would be no collapse by the leader.
A change in putters before the tournament gave Sabbatini's game a lift, and the new club came through again on No. 16 when he sank a 16-foot birdie putt to go back up by two.
Then he put his tee shot on the dangerous par-three 17th in the middle of the green.
Moments later, the horn sounded to signal a stoppage in play because of lightning in the area. The leaders found refuge in a van as heavy rain fell during a 28-minute delay.
But the threat to Sabbatini's lead had passed, and when play resumed he easily closed out the win.
Lee Westwood, who fell to No. 2 in the rankings behind Martin Kaymer on Feb. 28, shot 70 and tied for 29th. He needed a top-three finish to regain the top ranking.
Graeme McDowell shot a 64, matching the lowest score in the event since it moved to PGA National in 2007, and was 2 under for the tournament.
The average round was 2½ strokes above par. Since the beginning of 2010, only last year's U.S. Open at Pebble Beach has had a higher average — 4 over par.