Andrew Landry shot a record low opening-round score for a U.S. Open at Oakmont as he wrapped up a stunning 66.
The American sunk a birdie putt after returning to the course on Friday to conclude his round at the ninth hole - his last.
In so doing he wrote his name in the history books for the best first-round total on the occasion of Oakmont's ninth hosting of the major.
It gave him a clubhouse lead of two strokes.
Storms played havoc with Thursday's scheduled play as half of the 156-man field were unable to take to the course.
Of those that did, Landry was one of a select few to shoot under par, with the likes of Danny Lee, Bubba Watson and Lee Westwood also near the top of the leaderboard.
Defending champion Jordan Spieth was two over through 13 holes, while Rory McIlroy was two worse off across the first 14 holes.
World number one Jason Day tees off at 09:00am local time.