Zach Johnson's putter was as red-hot as the weather at Muirfield on Thursday, the 2007 U.S. Masters champion producing an outstanding 66 to move one shot clear of the field early in the British Open first round.
While the American was making an electric start to the third major championship of the year, world number two Rory McIlroy's troubles continued as he crashed to an eight-over 79.
Mark O'Meara was flying a surprise flag for the 'golden oldies'. The 56-year-old American moved to four-under through 12 holes, level in second place with Spain's Rafael Cabrera-Bello (67).
Most of the players were finding the treacherous knee-high rough difficult to cope with and scores were generally high on the banks of the Firth of Forth.
The parched and dry links course was also making it tough for the 156-strong field to control the ball on the fairways and the greens.
Johnson fared the best and he waved his putter like a magic wand to birdie the third, sixth and seventh and eagle the long fifth.
The 37-year-old made further inroads on par at the par-four 12th before dropping his only stroke of the day at the 14th.
"Any time you shoot under par in an Open or a major, for that matter, you have to be putting at least somewhat decent and I putted great," Johnson told reporters as temperatures rose to a balmy 80 degrees in East Lothian.
"This is the Open and you expect difficult conditions but a couple of the pin positions were pretty tough."
Johnson was pipped for the John Deere Classic title in Illinois on Sunday when he was beaten in a playoff by 19-year-old compatriot Jordan Speith.
"I felt great about last week, I'll be honest with you," he said. "I don't want to say I lost the golf tournament but I certainly had ample opportunities to win it.
"The last nine holes in particular I hit great shots, just didn't make many putts. If anything from last week, what I've embraced is the fact I'm playing great and I can put that into play, and I'm certainly confident in what I'm doing."
O'Meara matched Johnson's start with a barnstorming run of four birdies in six holes. Another birdie at the ninth took him to the turn in 31 before he faltered with a bogey at the 10th.
At the other end of the leaderboard, McIlroy dropped strokes at the fourth and fifth before getting one back with a birdie at the seventh.
McIlroy then frittered away shot after shot on the back nine, carding double-bogey sixes at the 12th and 15th, and he sported a look of sad resignation when he walked off the green at the end of another disappointing effort.
The Northern Irishman has struggled with his new Nike clubs all year, after deciding to ditch his old Titleist equipment, and is still searching for his first win of 2013 after topping the money lists on both sides of the Atlantic last season.
Phil Mickelson, bidding for back-to-back wins after landing the Scottish Open title in Inverness last week, fired an encouraging 69.
U.S. Open champion Justin Rose slipped to a 75 while title holder Ernie Els could manage only a 74 that included a double-bogey six at the 16th where he needed three strokes to get out of a greenside bunker.
Six-times major winner Nick Faldo, in his first competitive outing since 2010, marked his 56th birthday by returning a 79. Playing partners Tom Watson and Fred Couples fared better with matching 75s.
Late starter Tiger Woods made a poor start, bogeying the first hole after launching a wayward hooked drive into the rough.
The world number one then returned to level-par with a birdie at the fourth.