The third round was contested on Sunday after being postponed due to heavy rain on Saturday. The final round will take place on Monday. The Monday finish is the second of the season. The first came at the Ford Championship at Doral when Scott Hoch defeated Jim Furyk in a playoff.
Duffy Waldorf fired a 5-under 66 and stands alone in third place at 8-under-par 205.
Sabbatini had entered the round with a two-stroke advantage over four players. He started well with a birdie at the par-3 third, where he dropped a 3-iron within three feet for a birdie.
However, he dropped a shot when he three-putted for bogey at the par-4 seventh.
'I just made a couple of mental mistakes out there and I ended up making a couple of bad swings,' Sabbatini said. 'Unfortunately, I let it happen a little too frequently out there today, so I have to go out there tomorrow and work on that.'
Sabbatini closed the front nine in style with a birdie at the par-3 ninth. Around the turn, the South African carded three birdies and a bogey on the back side starting with a 10-foot birdie putt at the par-4 twelfth.
After parring the par-5 13th, he converted another birdie at the 14th. Sabbatini extended his lead to two shots with a birdie at No. 16. However, he stumbled with a three-putt bogey at the closing hole and saw his lead drop to one stoke.
'I'm very happy with the way I played,' said Sabbatini. 'It's always good to shoot under-par. But I left a lot of shots out there, so I was disappointed to do that. But you know, I managed to pretty much do what I was trying to, put the balls in the fairways and greens and get the job done from there.'
Sabbatini will look to pick up his first PGA Tour title since the 2000 Air Canada Championship.
'The situation being that a 62, 63 is out there, it's definitely possible,' he said. 'There's no room for complacency out there or getting ahead of yourself and thinking it's a match-play situation, because it isn't. I have got to go out there and do the job tomorrow and I'm going to have to play well.'
Fasth entered the round at minus-6. He quickly caught fire at the TPC at Avenel and birdied the par-5 second to get going. He followed that with a birdie at the next and made it three straight with a birdie at the par-4 fourth.
The Swede remained there until No. 10. At the 10th, Fasth sank his fourth birdie of the day. Fasth struggled with a bogey on the par-5 13th but came right back to birdie the next and finish alone in second.
'I played a really solid round of golf today,' Fasth said. 'I was very happy with pretty much every aspect of my game. I hit most fairways, hit almost every green. The greens are not that easy, so you're not going to roll in a lot of long ones.'
Reigning PGA Champion Rich Beem stands at 7-under-par 206. He is joined in fourth place by J.L. Lewis, Fred Funk, Tom Gillis, Padraig Harrington and Chris DiMarco.
Notah Begay III, Bernhard Langer, Marco Dawson and Hal Sutton share 10th place at 6-under-par 207.