Tim Petrovic (66), Billy Andrade (68) and Robert Allenby (65) share third place at minus-8.
Overnight leader Tiger Woods struggled on Saturday. He shot a 2-over-par 73 and fell into a tie for 28th place at 4-under-par 138.
'I didn't hit it well, I didn't putt well and I didn't chip well,' summed up Woods. 'I didn't control it. I could hit it left or right at any given time. It's tough to play when you're out there and you've got two ways going.'
Woods bogeyed three and six, but collected his first birdie at the par-5 seventh. He could not get up and down for par from a bunker at eight, but made par the next seven holes.
The No. 1 player in the world hit an awful drive at 16 and then missed the green with his second. Woods collected another bogey at that hole, but drained a 12-footer for birdie at 17 to get within five.
'Thank God this is a tournament where we have a Monday finish,' said Woods. 'I've got two rounds ahead of me, so I'm still in the ballgame; I'm only five back. Hopefully tomorrow I can go ahead and post another low number like I did yesterday and climb back up there.'
Browne began on the back nine Saturday and birdied the 11th when his 7-wood approach stopped 6 feet from the hole. He ran home a 20-foot birdie putt at 13, then parred 14 before a run of amazing golf around the turn.
He rolled in a 10-footer for birdie at the 15th and drained a 20-footer for birdie at No. 16. Browne, a two-time PGA Tour winner, kicked in a short birdie putt at the 17th and collected yet another birdie at 18 when he got up and down from the fringe. Browne sank a 12-foot birdie putt at the first to complete a run of five in a row.
Browne was alone in the lead at 10 under par after the five birdies in a row, but stumbled a bit. At the fourth, he three-putted from 25 feet, but then closed with all pars for a share of the 36-hole lead.
'I've been playing well since June and I just need to get past when I play well finishing 15th to 20th,' said Browne, who contended at this year's U.S. Open. 'So all I can do is keep stepping up at the plate and wait for my turn.
'I hit the ball solidly today, I only made one bogey and it was a three putt. Looking forward to playing tomorrow and the next day.'
Brehaut played the course from the first and broke into red figures in a big way. He knocked a 5-wood to 25 feet at the second hole and converted the eagle putt.
Brehaut dropped a shot at the fifth thanks to a bad drive, but that would be his last miscue. At the par-3 eighth, Brehaut hit a 4-iron to 4 feet to set up birdie.
On the back nine, Brehaut knocked a 6-iron to a foot for the easy birdie at 12. He hit another spectacular iron shot, an 8-iron inside a foot, for the tap-in at 15 and two-putted the par-5 last for his share of the top spot.
'I had a lot of chances today. It could have been better,' admitted Brehaut. 'It was looking like probably the most frustrating year of my of my life until the end of May, and now it's turned into the best golf year of my life. I'm just making a few more putts, getting a little more confident and hitting the ball pretty well.'
Joey Sindelar (68), Carl Pettersson (67), Briny Baird (69), Steve Lowery (69), Marco Dawson (66) and Will MacKenzie (68) are knotted in sixth place at minus- 7.
The 36-hole cut fell at 1-under-par 141 and among the notable former major winners who missed the mark were: Davis Love III (145), Shaun Micheel (145), David Duval (146) and Mark O'Meara (147).