Tiger Woods dropped four shots on the back nine to lose his momentum just as he looked poised to take the Open by the scruff of the neck in a sun-drenched third round.
The world number one eagled the fourth and seventh holes to lead the tournament for the first time.
But bogeys at the 11th, 13th, 15th and 17th meant a 69 that took him back to one over par for the tournament, two behind leader Thomas Bjorn who also shot a 69.
Denmark's Bjorn also eagled the fourth hole and birdied the ninth before nine straight pars on the back nine left him at one under, a shot clear of second-round leader Davis Love III, and two ahead of Woods, Fiji's Vijay Singh, Spain's Sergio Garcia, and Americans Ben Curtis and Kenny Perry.
Bjorn, who finished runner-up to Woods in the 2000 Open and also parred every hole on the back nine in the second round, was left in pole position to claim his first major title.
Woods fired his first eagle of the tournament at the par-five fourth before a spectacular bunker shot at the seventh sent the ball unerringly into the hole from around 40 feet.
He celebrated in uncharacteristically flamboyant style, raising both hands in the air and looking up at the sky, but kept his concentration sufficiently to notch another birdie with a 20-foot putt at the ninth before his problems on the back nine left him at one-over 214.
Singh, chasing his third major, birdied three of the last four holes to complete a round of 69, while Garcia holed a monstrous chip on the 17th green to save his par on the way to a 70, the same score as Perry and Curtis.
Love suffered four early bogeys to slip down the leaderboard before an eagle three at the 14th pushed him back to level par after a round of 72, well placed to challenge for his second major title.
Defending champion Ernie Els endured a frustrating day, slipping down the field before a birdie at the last left him five over for the tournament.