Brian Harman hit a sensational six-under-par 65 to race five clear of the field during round two of The Open.
The American holed four birdies on the trot from the second before sinking a 15-foot eagle putt on the last to move to 10 under par at Royal Liverpool.
Rory McIlroy’s 69 lifted him to one under, while Tyrrell Hatton had a nine at the last to end two over after a 73.
Joint overnight leader Tommy Fleetwood is among the later starters and resumes in second place on five under.
Argentina’s Emiliano Grillo, who shared the lead with Fleetwood, double-bogeyed the second as he fell back with a 74. South African amateur Christo Lamprecht is out on the course, meanwhile, and had four bogeys in his opening six holes.
But Friday morning was all about Harman, whose 65 was three shots better than the next best of the early starters – Australia’s Min Woo Lee, who climbed to joint fourth on three under with a 68.
His total of 132 shots matches that of Tiger Woods in 2006 and McIlroy in 2014 here at Royal Liverpool, and they both went on to win.
Left-hander Harman, who started one shot off the lead after Thursday’s 67, drained putts of 19, 25 and 17 feet on the second, third and fourth holes to go two ahead and further birdie followed on the par-five fifth.
“I’ve had a hot putter the past couple of days so I’ll try to ride it through the weekend,” he said.
A run of 12 pars was kept going on the 12th when Harman, who finished joint sixth last year at St Andrews, chipped in from the rough to avoid dropping a shot.
Just Stop Oil protesters briefly halted play at the par-three 17th hole with orange flares and powder but that was cleared well before Harman escaped with a par, after splashing out of a bunker to seven feet.
And he wrapped up an already superb round with a 240-yard second shot into the heart of the par-five 18th green before rolling in his eagle putt.
McIlroy reached halfway under par, but only after holing an eight footer for birdie on the last. The world number two missed two other birdie putts from closer in on a day when his scrambling skills came to the fore.
Six times he putted to save par after failing to reach the green in regulation, including a 14-footer on the 14th.
He had started brightly with two birdies in his opening five holes, but found the going tougher on the back nine, dropping shots on the 11th and par-five 15th.
The 18th has not yet yielded quite so many big scores as in round one, but England’s Hatton fell foul of the internal out of bounds, hitting two tee shots beyond the boundary as he closed with a quintuple-bogey nine that dropped him from two under to two over.
More to follow.