'That is probably one of the toughest days I've ever had on the golf course,' said Sabbatini, who earned $918,000 for the win. 'It just felt like everything I was doing was back-firing on me. I was hitting good shots, but nothing seemed to go as planned. I hit a lot of good putts out there, but looked like a terrible putter. We were just having trouble reading the greens.'
Fred Couples, a two-time champion of this event, bogeyed three of the last four holes to shoot 71 and ended the day alone in fourth place at 10-under-par 274.
Sabbatini led by four entering the round and kept that lead with a birdie on the first. His cushion slipped to two strokes after he bogeyed the third and fourth.
The South African got one of those strokes back when he made an 8-foot birdie putt on the sixth. Sabbatini parred five in a row around the turn. He nearly reached the green at the par-5 11th in two, but could only par the hole from right in front of the putting surface.
At the 12th, Sabbatini missed a 5-foot par putt to slip back to minus-13 and a share of the lead with Couples. Couples was playing steady golf as he birdied one, seven and 11 to move to 13 under.
Both Sabbatini and Couples bogeyed the 15th to create a four-way tie for the lead. Barlow, playing with Couples and Sabbatini, played the front nine at even par with two bogeys and two birdies.
Around the turn, Barlow birdied the 11th, then sank a 4-footer for birdie on 15 to get to 12 under and a share of the lead.
Scott, who was looking to follow Mike Weir as the second straight back-to-back winner here, was 2 under through six holes with three birdies and a bogey. Scott picked up five birdies on the back nine to fly up the leaderboard to minus-12.
'Starting out today, I figured I didn't have a chance,' Scott admitted. 'As I made the turn and birdied 10 and 11, the wind really started picking up. The leaders didn't jump out of the gate making birdies everywhere and I was slowly creeping up on them. I figured if I could get a few more, you never know what could happen.'
The Australian was in the clubhouse when Sabbatini, Couples and Barlow created the four-way tie at 12 under. As big a turning point as the 15th was, the 16th proved to be similar.
Barlow missed the green short at the par-3 16th and was unable to save par. Couples' tee shot hit a tree and landed in a greenside bunker. He blasted out, but could only two-putt for bogey.
'That was just a really bad shot,' said Couples of his tee shot on 16. 'I did not want to hit it left, and hit it the other way and got a lucky bounce into the bunker.'
Sabbatini moved back to the top of the leaderboard as he sank his 5-foot birdie putt on the 16th.
'I was frustrated with myself. I felt like I was sitting back and letting things happen and not being involved in it,' Sabbatini said. 'The 15th kind of woke me up. I was over done with sitting around and waiting. Then on 16, I started being aggressive again.
'It was a perfect yardage on 16. Today was the best I felt all week with my ball-striking, but that shot on 16 was a big shot. Then I got over the putt and said to myself, 'come on, if you can do this, you going to win this.''
Barlow could not get back into it as his birdie putt on 17 lipped out, then he two-putted for par at the last.
Couples went for the green at the par-5 17th, but missed the putting surface right. He left his chip short of the green. He pitched his fourth to 4 feet and made the par putt. Couples, though, three-putted from the fringe for bogey at the last to fall further back.
'On 17, I had my favorite club, 3-wood from a really good yardage,' stated Couples. 'I block, shanked it and scrambled to make par.'
Sabbatini left himself 17 feet for birdie on the 17th, but missed the putt right of the cup. The 29-year-old calmly two-putted for par from 45 feet out at the last to clinch his third PGA Tour win.
Lee Westwood posted a 3-under 68 to join John Rollins in a tie for fifth place at nine-under-par 275.
U.S. Ryder Cup captain Tom Lehman shot 69 to move into a tie for seventh place. He finished alongside Trevor Immelman, Carl Pettersson and Dean Wilson at minus-8. Bo Van Pelt was one stroke further back at 7-under-par 277 after closing with a 69.