FARMINGDALE, N.Y. — Brooks Koepka’s heart rate, he said Saturday night, probably would not vary much whether he was sitting on the couch watching the 101st P.G.A. Championship or sizing up a putt on Bethpage Black’s 72nd green to win it.
“I’d say I’m pretty flatlined most of the time,” he said.
Fast forward to dusk on Sunday. Koepka’s face was flush with anxiety as he stood on the par-3 14th green studying his fourth consecutive bogey putt. Poised to become the first man to hold back-to-back titles in two majors simultaneously, Koepka suddenly was staring at a more ignominious piece of history: He was in danger of becoming the first player to blow a seven-stroke, final-day lead in any PGA Tour event, much less a major.
“I was just in shock,” said Koepka, who weathered a back-nine wobble precipitated by wind that gusted to 30 miles per hour to successfully defend his P.G.A. title. He closed with a four-over-par 74 for a 72-hole total of eight-under 272, two strokes better than his close friend and training partner, Dustin Johnson, who whittled Koepka’s lead to one before bogeying two of his last three holes for a 69.
Koepka, 29, supplanted Johnson as the world No. 1 and joined Ben Hogan, Arnold Palmer, Jack Nicklaus and Tiger Woods as the only men to win four major titles in less than two years. He will seek his fifth major title, and his third straight United States Open crown, next month at Pebble Beach.
“That was a stressful round of golf,” Koepka said, adding that Johnson “did an unbelievable job of putting pressure on me.”
The conditions took their toll on everybody. Harold Varner III, who played with Koepka in the final pairing, posted an 81 — 14 strokes higher than his Saturday score. Paul Casey, who teed off more than five hours before Koepka and Varner, said the dog adorned in an emotional support jacket that he passed on his way to the scoring area “is what I feel like I need after playing that golf course.”
And Casey carded a 69, one of 11 sub-70 scores on Sunday.
The course is a beast in the most benign conditions, but on Sunday afternoon the winds kicked up, causing CBS’s blimp to evacuate the airspace above the course while Koepka was on the front nine. The wind wreaked havoc with Koepka’s shots throughout his bogey binge, which began at the par-4 11th. Koepka looked incredulous when his tee shot at the 149-yard par-3 14th got caught in gust and sailed the green.
The chants of “D.J.!” on 14 were meant to rattle Koepka. Instead, the fan’s embrace of his nearest rival helped him to refocus.
“It was like ‘I’ve got everybody against me — let’s go,’ ” he said.
Koepka’s success is a victory for late bloomers. He much preferred baseball as a child but grudgingly gave up the sport, he said, as he approached high school, “because I couldn’t hit a home run to save my life and I was a sucker for the curveball.”
That left golf, which Koepka learned on the public courses of West Palm Beach, Fla. He did not distinguish himself on the national stage as a junior player and was lightly recruited out of high school. Koepka wound up at Florida State, where he became a three-time all-American selection but did not win a college tournament until his senior year.
After college, he honed his game on Europe’s minor league circuit, the Challenge Tour, winning four times by a total of 23 strokes.
Koepka’s not one to cogitate over any shot; if he had his way, golf would be an anaerobic sport. And he does not lean on a sports psychologist to maintain a healthy outlook. He doesn’t have to because he isn’t one to let his score, good or bad, dictate his self-worth.
“If I would have bogeyed all the way in,” Koepka said, referring to the back nine, “I still would have looked at it like I tried my hardest. Sometimes, that’s all you’ve got.”
Graeme McDowell, the 2010 United States Open champion, said: “You can’t teach somebody to think the way that Brooks Koepka thinks. I wish I could think that way.”
Most players can better relate to Jordan Spieth, who spoke earlier this year about letting his bad rounds seep into his life off the course, or Rory McIlroy, who is building an impressive library with books that spread the perspective he articulated after winning the Players Championship in March: “I am not my score; I am not my results.” With this victory, Koepka passed Spieth, 25, who has three major titles but none since 2017, and equaled the major title total of McIlroy, who won his fourth at the 2014 British Open.
“He obviously gets into these mind-sets in the majors, and he really goes and gets into a different sort of state,” McIlroy said of Koepka, who has two PGA Tour titles outside the majors.
Koepka is like the baseball slugger Reggie Jackson in October, the hockey forward Justin Williams in May or the swing man Andre Iguodala in June; he is at his best when the pressure is at its greatest, as evidenced by the fact that all but two of Koepka’s career PGA Tour titles have come in the majors.
The one-time P.G.A. champion Rich Beem said Koepka reminded him of another four-time major winner, Raymond Floyd. “Just the way he attacks the game,” Beem said on Sunday after carding a 69. “The way that he thinks, the way that he talks, the way that he acts — nobody is going to intimidate him.”
In Palm Beach Gardens, Fla., just up the road from where Koepka grew up, Floyd watched most of the final round.
“I’m totally impressed with his play,” Floyd said of Koepka, adding. “When I got into the zone I always felt like I was playing the golf course — it was me against every hole — and I felt very confident leading and that’s what I see watching him.”