Rickie Fowler made light of the longest course in major championship history to produce a record-equalling start to the US Open on Thursday.
Erin Hills had been set up to play to 7,845 yards in the first round, surpassing the record set at Chambers Bay in 2015 by 150 yards, but a combination of wide fairways and a course softened by thunderstorms earlier in the week helped Fowler card seven birdies in a flawless opening 65.
That equalled the lowest score in relation to par in the first round of a US Open, Jack Nicklaus and Tom Weiskopf having both shot 63 in the first round on the par-70 layout at Baltusrol in 1980.
"I'd rather be remembered for something that's done on Sunday," said Fowler, who finished in the top five in all four majors in 2014 but has yet to win one of the game's biggest prizes.
"I didn't see seven under at the start of the week, but today is the best we are going to get. I just kept making putts when it mattered. It was nice. You don't get many rounds at the US Open that are stress-free. I knew I needed to drive it well and from there was just able to manage hitting and continuing to swing well and hitting good shots and rolling a couple in," he said.
Fowler, who was 25 over par for his previous four rounds in the US Open, started from the 10th and birdied the 11th, 12th, 14th and 18th to reach the turn in 32, before picking up further shots on the first, second and seventh.
That left the 28-year-old two shots clear of compatriots Brian Harman and Brooks Koepka and England's Tommy Fleetwood, with Ryder Cup star Patrick Reed on four under.
Lee Westwood, who is seeking his first major title at the 77th attempt, was a shot further back, but defending champion and world number one Dustin Johnson struggled to a three-over-par 75.
Fleetwood had missed the cut in his last two starts, but the 26-year-old from Southport made an ideal start with a birdie on his opening hole and added four more in a brilliant putting display.
"The course was as receptive as it's going to be but I never really tried to make a birdie, they just seemed to happen along the way," said Fleetwood, who finished second behind Johnson in the WGC-Mexico Championship earlier this season and lost in a play-off in the Shenzhen International in April.
"But towards the end I holed some great putts for par. No matter how fast you start or how many birdies you make the pars are the ones that keep you in it."
Asked if he would have taken a 67 at the start of the day, Fleetwood added: "I wouldn't have moved. That would have been fine. You don't really think about shooting five under at the US Open. Seven under is ridiculous."
Whether such low scoring continues remains to be seen, but Curtis Strange's place in history as the last player to win back-to-back titles looks safe unless Johnson can produce something special.
The 32-year-old carded a double bogey, two bogeys and a solitary birdie in his 75 to lie 10 shots off the pace, while playing partner and 2015 champion Jordan Spieth shot 73.
Johnson only arrived at Erin Hills on Tuesday afternoon after fiancee Paulina Gretzky gave birth to the couple's second son - named River Jones Johnson - on Monday, but had insisted his previous practice at the venue meant he was not "behind the eight-ball."
The day had started with confirmation that Phil Mickelson would miss the US Open for the first time since 1993 after the good weather ended his slim chances of making a last-minute dash to Erin Hills.
The 46-year-old needs to win the US Open, in which he has been runner-up a record six times, to complete the career grand slam, but announced earlier this month he would likely miss the event to attend the high-school graduation of his daughter Amanda.
Only a lengthy weather delay - and there have been several already this week - would have given the five-time major winner a chance of being at the ceremony and then flying by private jet from California to Wisconsin.
But when play started in perfect conditions, Mickelson informed USGA executive director Mike Davis he would not be able to play and left first alternate Roberto Diaz to take his place, alongside Stewart Cink and Steve Stricker, in a group due to tee off at 2.20pm local time.