Zach Johnson holed out for eagle on the four 18th Saturday to grab a one-stroke lead after 54 holes of the Chevron World Challenge.
Johnson, who did all of his scoring on the back nine, shot four-under 68 to end three rounds at eight-under-par 208.
Tournament host Tiger Woods bogeyed three of the five par-fives at Sherwood Country Club on Saturday. Overall, he mixed five bogeys and four birdies in a round of one-over 73. That dropped him into second place at minus-seven.
Woods is looking for his first win anywhere since the 2009 JBWere Masters. Johnson, who finished second to Woods at this event in '07, is going for his first title since winning at Colonial last year.
K.J. Choi rallied from early struggles to post an even-par round of 72. He ended three rounds at five-under-par 211.
Woods was alone in the lead for the first 12 holes. He knocked his third shot over the green at the par-five 13th. After chipping on, Woods two-putted for bogey to fall into a share of the lead with Johnson at minus-eight.
Johnson gave that lead right back to Woods. The former Masters champion made a mess of the par-five 16th and walked off with a bogey. Johnson followed with a three-putt bogey on 17 to fall two back.
"I'm not gonna think about 16 or 17. Sixteen has my number," Johnson admitted in a television interview. "I don't know (why I hit driver off the tee). It was into the wind, and I just double-crossed it. Then, I came out of the second shot. I definitely learned my lesson."
Woods hit his second shot into a hazard on 16 and took a drop. After he hit a poor chip shot, and was taking two putts to make bogey, Johnson grabbed the lead.
At the par-four 18th, Johnson split the fairway off the tee. From about 150 yards out, he hit a perfect second shot that trickled into the hole for eagle.
"I hit two good shots on 18. I would have been happy with four or three, but two is stealing," Johnson said in a televised interview.
Woods was unable to catch Johnson. He two-putted for par on 17 from nearly the same spot that Johnson had three-putted from. At the last, Woods' approach landed on the front of the green and he took two putts to get down.
"It was a tough day. I played the par-fives awful and I gave away a ton of shots, and consequently I lost the lead," Woods said in a TV interview. "Today was just a tough day. I hit good shots, but ended in bad spots."
Johnson parred the first 10 holes to remain at minus-four. One quick spurt moved him into a share of the lead.
He eagled the par-five 11th and followed with birdies on 12 and 13. As Johnson parred his next two holes, Woods came back to him.
Woods failed to keep any momentum all day. He birdied the first from two feet out, but tripped to a bogey on the par-five second. Woods chipped in for birdie at the fourth.
At the sixth, Woods failed to get up and down for par. He gave back another stroke with a three-putt bogey on the par-three eighth.
Woods sank a five-foot birdie try on the 10th, then two-putted for birdie on No. 11 to move to nine-under. He led by two at that point, but trouble loomed down the stretch.
"It was hard to determine where the wind was coming from," Woods said in a televised interview. "I've hit the ball well (this week), but I need to make more putts."
NOTES: Woods has won this title four times and finished second four times, including last year...Martin Laird, who started the day in last place in the 18-player field, fired a 66 for low round of the day, which helped him climb to one-over-par 217.