Tiger Woods' driver made its first appearance of the week today, but Lee Westwood now leads the 142nd Open Championship.
Woods had employed a conservative strategy over the first two days at a parched Muirfield and it looked to be paying dividends when he briefly moved into the outright lead early in the third round.
But the world number one was outshone on the fifth hole as playing partner Westwood made a brilliant eagle to vault to the top of a crowded leaderboard.
Both players had split the fairway on the 559-yard par five, Woods by using a driver for the first time, with Westwood then hitting his driver again and getting a good bounce to leave his ball just short of the green.
The 40-year-old, putting superbly since working with 1991 Open champion Ian Baker-Finch, was faced with a testing putt from around 35 feet but promptly holed it for a three to move to three under par.
Woods' second shot with a fairway wood had come up short left of the green and, after pitching to seven feet, the 14-time major winner missed his birdie attempt to remain two under.
Overnight leader Miguel Angel Jimenez, seeking to become the oldest ever major champion at the age of 49, was also two under after a dropped shot at the second.
Former Masters champions Zach Johnson and Angel Cabrera were a shot behind alongside four-time major winner Phil Mickelson and Sweden's Henrik Stenson, while Sergio Garcia and Brandt Snedeker led in the clubhouse on three over after rounds of 68 and 69 respectively.
Scotland's Martin Laird had seen his hopes of a famous home victory nosedive when he ran up a nine on the par-four third after taking two penalty drops from the heavy rough.