Reigning U.S. Open champion Retief Goosen, who shared the lead until four bogeys in his final six holes, managed a 1-under 69. He is tied for third place with former Masters champion Mike Weir (67) and Stephen Ames (70) at 5-under-par 205.
Woods, the 1998 champion, did not get off to the kind of start he needed on Saturday. He three-putted the first hole for bogey, but reclaimed the lost stroke when his approach nearly landed in the hole at three. Woods tapped in the short birdie putt, then let his putter take him to the top of the leaderboard.
Woods sank back-to-back 10-footers for birdie at the eighth and ninth holes. His third birdie in a row came from close to 30 feet and his fourth consecutive birdie was a 25-footer at the 11th.
At the 13th, Woods drove into the left rough, then came up short with his approach. He chipped 12 feet short of the hole, but drained the par save to keep his share of first.
Woods hit a 7-iron into the green for his second at the par-5 15th. He two-putted from 30 feet for another birdie to reach 9 under par. Woods parred his way in and now has a chance at his 41st PGA Tour victory.
'I played well the last two days and gave myself a good shot at it,' said Woods, who won this year's WGC-Accenture Match Play Championship. 'It feels real good.'
The 2004 season has not been great for Woods. He lost the top spot in the Official World Golf Rankings, fell to fourth on the money list and third in the rankings, failed to win a major and failed to even collect the stroke-play victory.
But Woods is spectacular with a lead after three rounds. In his career, Woods has held at least a piece of the 54-hole lead 32 times and in 30 of those, he visited the winner's circle. The last time Woods squandered the 54-hole lead was this event in 2000, when Phil Mickelson caught him on Sunday.
'It's going to be a great battle tomorrow,' said Woods. 'I've got a good buddy of mine out there with me.'
Haas is Woods' 'good buddy' as the two play several practice rounds together throughout the year and the two had similar starts on Saturday. Haas dropped shots to par at both the second and third holes, and two-putted from 90 feet to save par at the fourth.
'That was probably the key to my round,' said Haas, referring to his 15-footer for par at four. 'I was looking at 3 over through four, instead I kind of righted the ship. I played well from then on in.'
At the par-5 ninth, Haas came up short of the putting surface with his second shot. He chipped to three feet and converted the birdie try to get to minus-6.
Haas, who at 50 years of age is the oldest player to qualify for this event, birdied the 10th, then added another at No. 12.
When Woods took the lead at the 15th, Haas -- who played in the final group on Saturday -- followed him in with birdie. His 25-foot eagle try stopped turning right at the hole, so Haas settled for a tap-in birdie and a share of the lead at minus-9.
Haas ran home a 6-foot tester for par at 16, and closed with a 3-foot par putt at the last to join Woods in first.
While Woods is going through a slump without any wins since February, Haas' last victory dates back to the 1993 Texas Open. Haas held the 54-hole lead at last year's Players Championship, but fell victim to Davis Love III's amazing final-round 64.
Mark Hensby posted a 1-under 69 and is alone in sixth place at 2-under-par 208. Scott Verplank (68) and Jerry Kelly (71) are tied for seventh at minus-1.
Mickelson (67), Sergio Garcia (69), Darren Clarke (70), Zach Johnson (71) and Rory Sabbatini (71) are knotted in ninth place at even-par 210.
Vijay Singh, the No. 1 ranked player in the world, managed an even-par 70 on Saturday and is part of a group tied for 16th place at 2-over-par 212.