The 23-year-old Morikawa won his first major championship in only his second appearance in a major. The University of California, Berkeley graduate is the third-youngest PGA Championship winner in the stroke-play era — behind Rory McIlroy (2012) and Jack Nicklaus (1963) — and the ninth golfer to win the event in his debut.
Morikawa closed with a 64, the lowest final-round score by a PGA champion in 25 years. His weekend score (129) was the best in the final two rounds of a major by any player ever.
Morikawa finished two strokes ahead of second-place finishers Paul Casey (66) and Dustin Johnson (68). Bryson DeChambeau, Jason Day, Scottie Scheffler, Matthew Wolff and Tony Finau tied for fourth at 10-under 270.
Two-time defending champion Brooks Koepka closed with a 74, his worst round at this year’s event. He entered the final round in a three-way tie for fourth but slipped down the leaderboard with six bogeys and only two birdies.
Rory McIlroy finished 2-under par and tied for 33rd, just one stroke above Tiger Woods. Woods fell out of contention earlier this weekend but closed with a 67 to finish 1-under.
Justin Thomas, the world’s top-ranked player, also finished 1-under par and tied for 37th with Woods and four others. Jordan Spieth and Phil Mickelson ended in a tie for 71st at 4-over par.
