Tiger Woods fell back early, climbed back into the lead, then struggled early in the back nine to go one down to unheralded Gonzalo Fernandez-Castano after 13 holes in the Accenture Match Play Championship.
Fernandez-Castano won the first two holes before Woods managed to square the match on the seventh hole, and Woods moved to one-up with a birdie on 8.
In the past, when Woods dominated golf and was the kind of front-runner who simply never faltered in the lead, the match would have been all but over. But Fernandez-Castano managed to stay in the hunt and take advantage of Woods' mistakes.
On the back nine, Woods couldn't find the fairway. He double-bogeyed the par-four 10th hole then bogeyed the 11th to fall behind.
Pars on 12 and 13 left Fernandez-Castano, who didn't play an event on the PGA Tour last year because of a back problem, leading by one.
Woods, the former No. 1 who came into this tournament as No. 20, won this event in 2003, 2004 and 2008.