Tiger Woods double-bogeyed his final hole at the $US7.5 million ($NZ10.9m) WGC-NEC Invitational to fall back into a share of the second-round lead with Briton Luke Donald.
A triple winner at the Firestone Golf Club, the world number one had looked in complete control and was two strokes clear of
the field with five holes to play.
However, Woods suddenly lost his way.
He bogeyed the 14th and a double-bogey six at the par-four 18th left the 29-year-old American muttering to himself and angrily flailing one of his clubs.
He finished with a level-par 70 to join Donald, who shot 67, on four-under 136.
One shot back on a tightly-packed leaderboard was a group of five players led by world number two Vijay Singh and Sweden's Henrik Stenson, who shared the overnight lead with Woods but slipped back after carding matching one-over 71s. New Zealand's Michael Campbell was on 146, after recording a 74.
Irishman Paul McGinley (66), Dane Thomas Bjorn (67) and American Chris DiMarco (70) were also on 137.
Woods' problems at the 18th began when he sliced his tee shot into the trees on the right before hitting a branch with his second. The US Masters and British Open champion then overshot the green with his third.
"The good thing is I still have the lead," Woods told reporters. "We have got a long way to go but I didn't shoot myself out of the tournament by making a double-bogey and that's a good thing. I'm playing well so I just have to keep doing what I'm doing."
Donald is chasing his first win of the season after finishing runner-up at the Players Championship and tied for third at the US Masters.
"I got off to a little bit of a slow start but then really kicked in on 13 and got on a little bit of a roll," said the European Ryder Cup player.
' PGA champion Phil Mickelson came back down to earth, signing for a two-over 72 for a one-over tally of 141, while Australia's Stuart Appleby (70), Briton David Howell (68) and Sergio Garcia (70) are on two under.
- REUTERS
