A red-hot Rickie Fowler produced a record-equalling round to claim the clubhouse lead midway through day one of the U.S. Open, as softened greens and an initial lack of wind led to low scoring at Erin Hills.
A 7,845-yard course featuring lengthy fescue rough - albeit to the sides of appreciably wide fairways - was anticipated to provide a stiff challenge for the 156 competitors in the year's second major.
However, early conditions were conducive to low scoring and Fowler took full advantage with a superb 65 that matched the lowest score to par recorded in a U.S. Open first round. Tom Weiskopf and Jack Nicklaus also managed seven-under rounds at Baltusrol in 1980.
World number nine Fowler, who has yet to win a major, was two clear of Brooks Koepka, Brian Harman and Tommy Fleetwood. What is more, with the wind starting to pick up in the early afternoon, it appeared the later starters - such as Sergio Garcia, Jason Day and Rory McIlroy - would find life tougher.
However, Masters champion Garcia got off to a sensational start, eagling the first hole.
Playing alongside fellow high-profile names Hideki Matsuyama and Jon Rahm, who could only muster disappointing respective scores of 74 and 76, Fowler birdied three of his first five holes after starting on the 10th.
Three successive gains from the 18th further improved the American's position and he also picked up a shot at the seventh before finishing with two pars.
Koepka, Harman and Fleetwood all shot 67, while Patrick Reed also made it to five under at one stage but finished one worse off.
Twenty-eight years have passed since the last successful U.S. Open defence, courtesy of Curtis Strange in 1989, and Dustin Johnson has much work to do if he is to buck that trend.
The world number one found the fescue on a regular basis on his opening nine and had to settle for a three-over 75.
Jordan Spieth and Martin Kaymer - the champions of 2015 and 2014 respectively - shot 73 and 72 respectively in the company of Johnson.