The USGA pledged to ease off the severe conditions at Shinnecock Hills. We go through all the key moments of Sunday's final round.
And while the burly American became a figure to be genuinely feared, Tommy Fleetwood emphasised that he is the Briton knocking most loudly for admittance to the major winners' club. He tied the record held by five others at 63, including Johnny Miller when he won in 1973 - the only time a 63 was shot in the Open's last round.
The insane run also made him the early clubhouse leader at 2-over par, just a few hours after he began his round tied for 23rd and six shots off the top.
Fleetwood finished at 2 over and Koepka never lost the lead.
That 62 would have moved him to one-over for the tournament, and into a tie with Koepka who hooked his shot into the 18th green into the grandstand and settled for a bogey and one-over finish.
"It would just be nice, if I'm not sitting here wishing I made cut at five or six over", said Fowler, who teed off at 2:26 p.m. "Because it could have been a big momentum shift there, and we could have been playing tennis just going back and forth".
In the last 22 groups on Saturday, no one even matched par-70 on the treacherous layout.
At the par-3 11th, Finau rolled in a 27-foot birdie putt to get within two of the lead, but fell back at the next hole when he three-putted for a bogey. So Shinnecock Hills was relatively tame in the final round.
"The only one I haven't figure out is Augusta - hopefully I'll figure that one out soon". "The worst thing that could happen is if something did happen and then I wasn't really ready", Fleetwood said. "You're always going to be a bit disappointed to come up one short in a major but I'll give it another go".
With scores fluctuating on a round-by-round basis, Johnson's differential between the second and third round was 10 shots - 67 on day two followed by a 77 yesterday.
Koepka opened with a 75 Thursday, the highest first-round score by a US Open champion since Raymond Floyd at Shinnecock Hills in 1986. "But I'll tell you what, it was a long four months".
A year ago, Johnson called him on the eve of the final round to offer advice.
"They are the ultimate tests of golf and it shows you where you are at and what you need to improve".
"To have my name on it twice is pretty incredible, and to go back-to-back is even more extraordinary", Koepka said. If DJ gets course conditions anywhere close to what we saw on Sunday, I think he wins by two or three. "It would have been fun to dual it out with him coming down the end, having to make some putts".
The soft-spoken, shaggy-maned, jam-band-looking Fleetwood (who Dan Jenkins once perfectly congratulated for being "low guitarist" at the Masters) had begun attracting groupies left and right; despite endless heckles at the likes of Ian Poulter, the Long Island crowd was fully embracing a Brit at its national championship. Ben Hogan, Curtis Strange and now Koepka are the only men to do it since World War II. Next up is Pebble Beach, and a chance to join Willie Anderson as the only player to win three in a row. Ben Hogan won three straight that he played, missing in 1949 after almost getting killed when his auto struck a bus.
Then they waited for more than four hours while the course brought the rest of the field back to them.