Gullane, United Kingdom: Lee Westwood briefly grabbed a share of the Open lead on Friday when he went five under after 12 holes of the second round.
The English, former world number one was rock steady with a 72 on Thursday but he bolted out of the blocks second time out with three birdies in the first five holes.
He reached the turn in five under 31 and added a birdie at the 12th to tie for the lead at five under with American Zach Johnson, who had a mid-afternoon tee-off time.
Westwood left himself with a monster putt at the next hole, however, left his lag effort six-foot short, and dropped his first shot of the day.
Top Scot Martin Laird had four birdies in a row from the ninth to get to three under before dropping one at the 14th.
Northern Ireland's 2011 Open champion Darren Clarke also briefly climbed onto the leaderboard with three straight birdies from the second, but he came to grief at the sixth, taking two to get out of a pot bunker en route to a quadruple bogey eight.
Tournament favourite Tiger Woods, handily placed after an opening 69, made a solid start with three pars, followed by a birdie at the third, where he sunk a 12-footer.
He narrowly missed an eagle at the fifth, but pushed another short putt wide at the eighth.
Veteran fellow American and close friend Mark O'Meara, equal second overnight on 67, fell away with a seven over 78.
Luke Donald, who had a nightmare round of 80 on Thursday started to claw his way back with birdies at the first and third, while Masters champion Adam Scott dropped two on the way out to stand at two over.
Phil Mickelson (69), Justin Rose (75) and defending champion Ernie Els (74) all had afternoon tee-times as did Rory McIlroy, who was looking to bounce back after a crippling opening round of 79.