Koepka won his first major championship, and he did it in record-tying style. For the 27-year old golfer, it is his eighth and biggest professional victory.
Benign conditions on Thursday made for a feast of low-scoring, with a record 44 players dipping under par - the most ever in the first round of the US Open.
"It was a long phone call for us - it was like two minutes", Koepka said. I think I preferred watching the Woods era but it is also fantastic to see people win their first Majors, as we did at the weekend. "It hasn't sunk in, obviously, and (it) probably won't for a few days".
England's Tommy Fleetwood was unable to keep pace with playing partner Koepka, carding a final round 72 to end fourth on 11-under. The shots he hit down the stretch, you can't describe how hard some of them are. Koepka bogeyed the par-4 10th hole, marking the first time he registered a bogey on the back nine during the tournament.
He was back in the spotlight on Sunday, though, and he responded with a six-under-par round.
Harman finished with a bogey on 18.
"I don't want to say homesick".
But she told him: "You have to be able to give a punch and take a punch, in golf and in life". He went and won the golf tournament on the back nine.
"I had an opportunity today and didn't get it done". I don't want to say I was homesick, I was just exhausted of golf, exhausted of travelling.More news: PlayerUnknown's Battlegrounds Sells 4 Million Copies in Three Months
"I'd won once on the (US) PGA Tour, once on the European Tour".
Nonetheless, the birdie that started the string of three straight did wonders for Koepka's confidence.
But mostly, the phenomenal scores pointed to the wave of new stars, such as Koepka, who sometimes obscure each other. "Unfortunately, I just didn't execute". Palmer shot a 65 after going into the final round trailing by seven shots.
"It bites a little bit right now", Harman said afterwards.
This year's U.S. Open was not only an impressive display of Brooks Koepka's talents and his intense competitiveness, but it also showed off the depth in the men's game, particularly with the young Americans. I just felt like I should be winning more. I'm a good ball-striker and a couple of these par-fives I don't even need to hit driver, I can still get there.
Brooks Koepka didn't just win his first major tournament on Sunday at Erin Hills Golf Course, he made history doing it. Only four left-handers - Bubba Watson, Phil Mickelson, Mike Weir and Bob Charles - have won major championships. It was an especially good day for Spieth considering how the wind picked up at Erin Hills.
They are close friends on the golf course and in the gym, and they play a similar game of power off the tee, a clean strike with the iron and a knack for looking calm even as the pressure is ramping up.
"I learned a lot this week", Matsuyama said. "I come from a baseball family, and it's in my blood".