"I called my manager Blake Smith that night and I was like 'I don't even want to play this final round - I just want to go home'. I was just tired of golf, tired of travelling. Even though I had the lead, I just wanted to get out."
Smith talked him out of it and Koepka duly went on to win, collecting $44,000 and a 44 ($77) trophy. Straight afterwards, Koepka jumped into his car to drive through the night to contest Open qualifying at Sunningdale, before a tyre blowout put him on an early flight instead.
Koepka underlined his talent by shooting rounds of 69 and 65 to win the qualifier and book his place at Muirfield. That was his second major and he missed the cut, but he finished fourth in the next year's US Open and with two more top fives in the majors in the next two years arrived at Erin Hills last week ready to fulfil his destiny.
Koepka did so with an emphatic ball-striking display - hitting a remarkable 62 out of 72 greens in regulation - and equalling Rory McIlroy's record US Open low score to par of 16-under, beating Brian Harman and Hideki Matsuyama by four shots.
This time the winning cheque was for $2.9 million and the sterling silver trophy is, of course, priceless. It has been a unique route to glory for an American golfer but to the world No 10, it was so obviously worth it.
"It helped me ... really figure out that, 'Hey, play golf, get it done and you can really take this somewhere.'
"When I came here I'd only won once on the PGA Tour, once on the European Tour. [I don't enjoy] losing and I just couldn't stand ... that I'd only won twice."
