Tiger Woods surrendered his overnight lead to a charging Geoff Ogilvy in the third round of the Target World Challenge on Saturday.
The world number one fired a two-under-par 70 in damp, cool conditions at Sherwood Country Club to slip one shot behind the Australian.
A stroke in front with three holes to play, Woods bogeyed the par-five 16th before a scrambled par at the last earned him a tie for second place at 10-under 206 with fellow American Chris DiMarco (68).
U.S. Open champion Ogilvy, boosted by four birdies in the first seven holes, lost the outright lead three times before regaining it with a birdie-three on the final hole for a best-of-the-day 67.
"I played good all day, really," Ogilvy told reporters. "I started very well, birdied the first two holes, and that's always nice when it's tough.
"It didn't look like it was going to be a fun day when we walked out of the locker room this morning and it was cold and raining and the forecast was for it to get worse.
"I hit a couple of bad shots on the way in but on a Saturday you just want to keep yourself in the golf tournament, especially on a day like today.
"Being in the last group tomorrow is always where you want to be," added Ogilvy, who will tee off at 1900 GMT in Sunday's final round with DiMarco.
Swede Henrik Stenson dropped five shots over the last six holes on his way to a 73 and a share of fifth place with American David Toms (68) at six under, one behind Britain's Paul Casey (70).
Tournament host and twice champion Woods, one stroke clear overnight, rattled up four birdies and two bogeys to stay in the hunt for his 11th title of the year worldwide.
"Geoff is playing great and so is Chris," the 12-times major winner said. "But I'm right there with a shot to win the tournament tomorrow.
"Hopefully I can play a little bit better than I did today and make some birdies."
A superb approach to within six feet of the flag at the par-four first set up birdie number one and he picked up his second shot after reaching the green in two at the par-five second.
Playing partner Stenson also birdied the opening par-five before trimming Woods's lead to one by spectacularly holing out from a greenside bunker at the par-three third.
Ogilvy joined Woods at the top of the leaderboard after his four-birdie run before the world number one slipped back with a bogey at the par-four seventh, where he failed to reach the green in two.
The Australian's outright lead was shortlived, though.
Woods, champion in 2001 and 2004, hit his tee shot to 10 feet at the par-three eighth and rolled in the putt for his third birdie of the day.
He then parred the ninth to reach the turn at 10 under, deadlocked with Ogilvy.
The Australian twice forged ahead in the afternoon sunshine, following birdies on 10 and 13, before Woods again drew level after holing a 35-foot birdie putt at the par-five 13th.
Ogilvy missed a five-footer on 15 to slide back before Woods made his second bogey of the day at the par-five 16th where he missed the fairway off the tee, found a hazard with his second shot and a greenside bunker with his third.
The unflappable Australian finally regained the outright lead when he hit his nine-iron approach to just two feet at the last, the tap-in putt earning him his seventh birdie of the day.
World number four Adam Scott, despite carding his best round of the week with a 69, stayed rooted to the bottom in the 16-man field at eight over par.
Britain's Luke Donald, champion at Sherwood Country Club last year, was only two strokes better after returning a 72 that featured birdies on the last three holes.