Open leader Lee Westwood’s bid to win a first major got off to a good start - before he had completed one hole.
World number one Tiger Woods and Masters champion Adam Scott both bogeyed the first to extend the Englishman’s lead, and a par at the 447-yard opener, two-putting from 25ft, consolidated that.
Westwood went to the second tee still three under, with playing partner Hunter Mahan – also looking for his first major – an inch short of a birdie at the first and remaining two shots back.
Playing in the penultimate group, Woods, who has never won a major when he did not hold the 54-hole lead, could only find the front of the first green and three-putted from distance.
Scott, having had to splash out from a fairway bunker, flew through the back of the green to also bogey.
Woods and Scott parred the second to remain respectively three and four shots back.
Sweden’s Henrik Stenson, one over when he started, holed a monster putt on the first and birdied the third to move to one under.
Further down the field, England’s Ian Poulter made a charge with a birdie at the fifth, eagle at the par-five ninth and another birdie at 10 to move to two over and into a tie for seventh place.
Westwood's lead was cut to one by the third as he found trouble off the tee, pulled his approach and although he chipped to 12 feet he could not make par.
Stenson was the nearest challenger, in outright second place after playing five holes, after Mahan bogeyed the second to drop to even par, which was where Poulter moved to as his impressive charge continued.
He birdied the 11th and 12th to move to even par with all the momentum behind him and narrowly missed another birdie chance from nine feet at the short 13th.
His position started to look even better, however, as Scott dropped a shot at the 226-yard fourth to slip to two over with Woods three-putting from distance for the second time in his round to be one over.