The American was one of four players sharing the lead overnight heading into the final round of competition.

England's Tommy Fleetwood would steal most of the attention before the leaders began their rounds, as he produced a stunning display to move into contention.

He achieved four birdies and a bogey on the front nine to boost his chances of earning a maiden major title.

A run of four birdies in successive holes would help Fleetwood card a seven-under-par round of 63, the joint lowest in US Open history.

It gave the Englishman the clubhouse lead and he was left to watch as his rivals looked to push him down the leaderboard.

Koepka was the man to achieve the feat, as he managed five birdies and two bogeys in his round to head onto the 18th with a two shot cushion over Fleetwood.

A bogey would see the American finish with a two-under-par round of 68, leaving him one-over-par for the tournament.

It proved enough to secure the title for the second straight year.

Koepka, whose first major came at the event last year in Erin Hills, became the first player to defend the title since Curtis Strange.

The American won in both 1988 and 1989.

Koepka is only the seventh player to accomplish winning the event in two consecutive years.

World number one Dustin Johnson would have to settle for third place, two shots behind the winner.

He was followed by fellow Americans Patrick Reed and Tony Finau, who finished at four and five-over-par for the tournament respectively.