Brooks Koepka, the 29-year-old Florida golfing phenom, won the 2019 PGA Championship on Sunday for the second year in a row, as he shot eight under par at The Black Course in Farmingdale, New York, for a final round score of 74, defeating Dustin Johnson by two strokes. This is Koepka's fourth major championship, as he won the 2017 and 2018 U.S. Open and the 2018 PGA Championship.

Koepka became the first player since Tiger Woods in 2006 and 2007 to win the PGA Championship in back-to-back years. He did so in dominating fashion, entering final round play with a massive seven stroke lead, though Dustin Johnson made things difficult for him in final round play.

"I'm just glad we didn't have to play anymore holes. That was a stressful round of golf," Koepka said upon receiving the Wanamaker Trophy. "DJ played awesome, but I'm glad to have this thing back in my hands."

Brooks Koepka of the United States kisses the Wanamaker Trophy during the Trophy Presentation Ceremony after winning the final round of the 2019 PGA Championship at the Bethpage Black course on May 19, 2019, in Farmingdale, New York. Getty

Johnson, the world's No. 1 ranked player, gave Koepka a run for his money during final round, as he parred five holes on the back nine to finish only two strokes from victory. Johnson shot a final round score of 69 to finish six under par, as he and Koepka dueled before a rowdy Suffolk Country crowd at The Black Course at Bethpage State Park public golf course.

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"He did an unbelievable job putting pressure on me," Koepka said.

While Johnson's near-final round comeback created high drama Sunday, Koepka was the real story. Koepka came into final round play with a stunning seven-stroke lead. Koepka led throughout the tournament, and he became the first player to go wire-to-wire in the PGA Championship since Hal Sutton in 1983.

Koepka's seven stroke lead after the first three rounds was the largest 54-hole lead in the PGA Championship since its 1958 switch to stroke play. The Florida-born professional had to feel good about his chances coming into final round play, as no one had ever lost a seven-stroke lead in 159 years of major championship golf.

Brooks Koepka of the United States reacts to his putt on the 18th green during the final round of the 2019 PGA Championship. Getty

But on Sunday, he played his poorest outing of the week, mainly due to gusty 20-to-25 mph winds. Koepka started out well on the front nine as he birdied hole 4, a par-5, and then parred holes 5 through 9. He seemed poised to run away with the championship.

But the back nine was a whole different story for Koepka. He encountered some trouble on 11, a par 4 which he bogeyed, having shanked his tee-shot into a sand trap. He then bogeyed hole 12, decreasing his lead to 4 strokes. He then hit his tee-shot on 13, a par five, completely off the green. It took almost 10 minutes to move the crowd out of the way so he could hit his shot back onto the fairway. Koepka eventually bogeyed the hole.

For a moment, it seemed like the greatest collapse in the history of golf actually was imminent. Koepka's lead was shaved from seven to two, thanks to an impressive back nine by Johnson.

Brooks Koepka of the United States reacts after putting in to win on the 18th green during the final round of the 2019 PGA Championship. Getty

Koepka's biggest competition came from the South Carolina-born Johnson, who came into final round play in second place, trailing by those seven strokes. Johnson shot three birdies on the front nine on holes 4, 6 and 9. On the back nine, Johnson parred holes 12, 13 and 14. He then birdied hole 15, for the fourth time in the tournament. Koepka then shot his fourth straight bogey on hole 14, which brought his lead down to a single stroke. The crowd at Bethpage could sense history, and many fans started to chant "DJ! DJ!" while Koepka walked to his ball, the glint of concern in his eyes betraying a consistently stoic demeanor.

But Johnson was done in by a collapse of his own, as he shot a bogey on hole 16, missing a crucial short putt, and another bogey on 17 to eliminate any chance of victory. Koepka calmed down to par holes 15 and 16 to give himself a two stroke lead heading into the final two holes.

The amateur-turned-pro finally closed out Johnson on hole 18. Holding a two shot lead, Koepka hit his tee-shot into the rough, but he rallied to hit a beautiful approach on the green that allowed him to par the hole for the victory. This is Koepka's fourth major championship despite the fact that he's only been a professional golfer for 23 months. He has finished first, second and first in his last three majors.

By finishing as the runner-up Sunday, Johnson became one of the few professional golfers ever to finish as runner-up in all four major tournaments, though he won the 2016 U.S. Open.

"The golf course played extremely difficult. The wind was really, really blowing," Johnson said after Koepka's major win. "I'm very pleased with the way I played today in these conditions and I gave myself a chance."