(CNN) The coronation had more spice than he would have liked, but Brooks Koepka held his nerve to seal back-to-back PGA Championship titles to confirm his status as a once-in-a-generation player.

The 29-year-old refocused after a serious wobble to triumph by two shots from the fast-finishing Dustin Johnson to become only the fourth player to score four major titles in the span of eight starts after Ben Hogan, Tiger Woods and Jack Nicklaus.

The muscled Floridan is the first player to win his first four majors inside two years and the first in history to win two back-to-back majors concurrently after also landing consecutive US Opens in 2017 and 2018.

Koepka led by seven going into the final day and looked to be coasting to the Wanamaker Trophy before a mini meltdown -- four straight bogeys -- on the back nine dropped him back to just one clear of close friend and then world No.1 Johnson, the only other player in his ballpark.

Rowdier elements of the already raucous New York crowd chanted "DJ, DJ" at Koepka as they sensed late sport in the bearpit of Bethpage Black.

Memories raced back to other famous collapses, such as Jordan Spieth's Masters misfortunes when he squandered a five-shot lead with nine to play in 2016. Or the similar Augusta agonies of Rory McIlroy or Greg Norman.

But with Koepka at his mercy, Johnson faltered at the 16th and 17th to finish six under, and though Koepka dropped a shot at the 17th he had done enough to seal a wire-to-wire victory in a record-breaking week which also took him back to the top of the world rankings.

"That was a stressful round of golf, DJ [Johnson] played awesome. I'm just glad to have this thing back in my hands," Koepka said at the trophy presentation ceremony on the 18th green.

"I kid you not, I heard the chants, I heard everything. He did an unbelievable job putting pressure on me.

"It's incredible, I don't even know if I dreamed of this. This is so cool."

Photos: In pictures: The 2019 PGA Championship so far Brooks Koepka successfully defended his PGA Championship title after a thrilling finish at Bethpage Black. Hide Caption 1 of 36 Photos: In pictures: The 2019 PGA Championship so far The 29-year-old clinched his fourth major in eight events after overcoming a late wobble at Bethpage. Hide Caption 2 of 36 Photos: In pictures: The 2019 PGA Championship so far Koepka led by seven ahead of the final day but four straight bogeys on the back nine let in his close friend and the then world No.1 Dustin Johnson, who narrowed the gap to one. Hide Caption 3 of 36 Photos: In pictures: The 2019 PGA Championship so far England's Matt Wallace was in the chasing pack well behind the leading two at Bethpage. Hide Caption 4 of 36 Photos: In pictures: The 2019 PGA Championship so far Popular veteran Phil Mickelson is a fan favorite in New York. Hide Caption 5 of 36 Photos: In pictures: The 2019 PGA Championship so far Koepka said the back nine was "very stressful" as he battled his own mistakes and the pressure exerted by Johnson. Hide Caption 6 of 36 Photos: In pictures: The 2019 PGA Championship so far Japan's Hideki Matsuyama of Japan chips onto the 13th green during the final round of the PGA Championship. Hide Caption 7 of 36 Photos: In pictures: The 2019 PGA Championship so far Tyrrell Hatton of England makes a shot out of the rough amidst the gallery on the ninth hole during the final round. Hide Caption 8 of 36 Photos: In pictures: The 2019 PGA Championship so far Three-time champion Jordan Spieth finished tied third to reignite his major form after a slump of late. Hide Caption 9 of 36 Photos: In pictures: The 2019 PGA Championship so far Johnson faltered coming home and has now finished runner-up in all four of golf's major tournaments. Hide Caption 10 of 36 Photos: In pictures: The 2019 PGA Championship so far Brooks Koepka drives off the 12th tee during the third round. Hide Caption 11 of 36 Photos: In pictures: The 2019 PGA Championship so far Jordan Spieth hits out of a bunker onto the fifth green during the third round of the PGA Championship golf tournament on Saturday, May 18. Hide Caption 12 of 36 Photos: In pictures: The 2019 PGA Championship so far A spectator rests in the shade of a tree along the seventh fairway during the third round. Hide Caption 13 of 36 Photos: In pictures: The 2019 PGA Championship so far Phil Mickelson walks up to the 18th green during the third round. Hide Caption 14 of 36 Photos: In pictures: The 2019 PGA Championship so far Dustin Johnson greets spectators as he walks to the 12th tee. Hide Caption 15 of 36 Photos: In pictures: The 2019 PGA Championship so far Brooks Koepka picks his ball out of the hole after putting on the eighth green. Hide Caption 16 of 36 Photos: In pictures: The 2019 PGA Championship so far Brooks Koepka plays his shot from the 17th tee during the second round of the 2019 PGA Championship on Friday, May 17, in Farmingdale, New York. Koepka, in the lead after the second round, set a record for the lowest 36-hole score in major championship history. Hide Caption 17 of 36 Photos: In pictures: The 2019 PGA Championship so far Tiger Woods tees off on the 18th hole. Woods failed to make the cut for the final two rounds after shooting a three-over 73, ending the tournament at five over. Hide Caption 18 of 36 Photos: In pictures: The 2019 PGA Championship so far Fans cheer for Tiger Woods on the 13th hole. Hide Caption 19 of 36 Photos: In pictures: The 2019 PGA Championship so far Jordan Spieth of the United States lines up a putt on the 16th green during the second round of the US PGA Championship. At the end of the round, Spieth was tied second with Australian Adam Scott. Hide Caption 20 of 36 Photos: In pictures: The 2019 PGA Championship so far Fans line up near the the eighth green during the second round. Hide Caption 21 of 36 Photos: In pictures: The 2019 PGA Championship so far World No.1 Dustin Johnson reacts after putting on the seventh green. Hide Caption 22 of 36 Photos: In pictures: The 2019 PGA Championship so far Phil Mickelson plays a shot from the rough on the third hole. Hide Caption 23 of 36 Photos: In pictures: The 2019 PGA Championship so far Brooks Koepka, left, shakes hands with Tiger Woods after finishing the second round. Hide Caption 24 of 36 Photos: In pictures: The 2019 PGA Championship so far Tommy Fleetwood plays a shot from the fourth tee. Hide Caption 25 of 36 Photos: In pictures: The 2019 PGA Championship so far Brooks Koepka with yet another impeccable drive on the 15th tee in a thrilling opening round of 63 -- a course record. Hide Caption 26 of 36 Photos: In pictures: The 2019 PGA Championship so far April's Masters victory felt a long time ago for Tiger Woods; the 15-time major winner regularly located both rough and bunker in a first round that lacked the control of last month. Hide Caption 27 of 36 Photos: In pictures: The 2019 PGA Championship so far Alex Noren takes stock on the third hole of this thrillingly difficult golf course. If you miss the fairway and the bunkers, the long grass will eat you alive. Hide Caption 28 of 36 Photos: In pictures: The 2019 PGA Championship so far John Daly, the PGA Championship winner in 1991, was making a bit of history at Bethpage Black. He has been given permission to use a golf cart at the tournament as a result of his osteoarthritis in his right knee. Hide Caption 29 of 36 Photos: In pictures: The 2019 PGA Championship so far Phil Mickelson and Jason Day salute their fans as they complete solid first rounds of 1 under par. Hide Caption 30 of 36 Photos: In pictures: The 2019 PGA Championship so far Flowing locks blowing in the wind, Tommy Fleetwood in action en route to a very respectable first-round effort of 3 under par. Hide Caption 31 of 36 Photos: In pictures: The 2019 PGA Championship so far Brooks Koepka putts on a hulking eighth green, watched by fans who were witnessing a clinic from the three-time major winner. Hide Caption 32 of 36 Photos: In pictures: The 2019 PGA Championship so far Jason Day's only major victory came in the 2015 PGA Championship. Here he is, one of many to find one of Bethpage Black's daunting sandpits. Hide Caption 33 of 36 Photos: In pictures: The 2019 PGA Championship so far Dustin Johnson, the world No.1 and a favorite among many experts, tees off at the 17th. Hide Caption 34 of 36 Photos: In pictures: The 2019 PGA Championship so far As Phil Mickelson watches his tee shot fly into the distance, his fans make sure to leave with their own memories. Hide Caption 35 of 36 Photos: In pictures: The 2019 PGA Championship so far An image to highlight the extent of this monster golf course. Narrow fairways, damp, long roughs, gaping bunkers, overhanging trees. But then, Brooks Koepka on the tee, helping himself to the most supreme first round of major golf imaginable. Hide Caption 36 of 36

Heir apparent

Like Arnold Schwarzenegger's Terminator, the indomitable Koepka has emerged from the firestorm of hot young pros trying to be The Next One. His major charge would seem to suggest he is the true heir apparent to Woods, the Masters champion he beat by 17 shots after two rounds.

Koepka was six when Woods won the first of his 15 majors at the Masters in 1997, and he grew up with his countryman's notion that golfers should be athletes. His gym-sculpted body facilitates eye-watering power which he marries to a soft touch and an unblinking focus. While Koepka may have only won two regular PGA Tour events, his prowess on the hardest courses and in the most difficult conditions has turned him into a major machine.

Other players have enjoyed major runs in short bursts, such as McIlroy, whose four titles came in just over three years, or Padraig Harrington's three in just over a year.

But Koepka's kind of domination of majors has not been seen since Woods' six titles between 2005 and 2008. If the former world No.1's epic 2000-2001 run, when he held all four titles at the same time, is still the benchmark of supremacy, Koepka's current tear suggests no one would be surprised were he to get close. No player has won three straight US Opens since 1905, yet Koepka will go Pebble Beach next month as the hot favorite.

"It's been so much fun these last two years, I don't think anybody thought I would do it that fast," Koepka told a press conference. "To be standing here with four majors is mind blowing. Today is the most satisfying because of how stressful that round was. I know for a fact that was the most excited I've been in my life there on 18."

Brooks Koepka leaked four straight bogeys on his back nine to set up a dramatic finish.

'Motivation'

Koepka revealed earlier this week he has a "number" in mind for major titles. "I don't see why you can't get to double digits [majors]," he told reporters. Only Walter Hagen (11), Woods (15) and Nicklaus (18) have ever won more than nine major titles in the men's game.

But for all his explosive exploits on the golf course, Koepka treads a paradoxical line with his public image. He's naturally reticent to be in the spotlight, and yet is riled easily when he perceives he is not getting the attention he should.

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"There's always a chip, I think every great athlete has a chip on their shoulder," he told reporters at Bethpage. "I use it as motivation to prove people wrong."

His deadpan demeanor on the course is a deliberate ploy to stay focused and guard against his hot-headedness as a youngster, he says. But it works against him in the public eye as fans and the media crave characters.

The young Koepka took up golf after a car accident ended his dreams of making it in baseball, basketball and other more athletic sports.

After college at Florida State, he opted against following his contemporaries through the usual qualifying school route to a professional career in the US and took up membership of Europe's second-tier Challenge Tour in 2012.

He traveled widely, from Kenya to Kazakhstan, learning his trade, gaining life experiences and growing up. "It was the best time of my life," he has said.

Four victories secured his European Tour card and a win in Turkey in 2014 propelled him back onto the US PGA Tour where he picked up a first title the following year.

Koepka discovered his major mojo at the 2017 US Open at Erin Hills, and is now building a body of work that could serve as a blueprint for future generations.