Brooks Koepka survived a late stumble to retain the PGA Championship by 2 shots, after starting the day seven ahead. The win marks his fourth major in the last two years.

Koepka, 29, went into the final round with a seven-stroke lead at Bethpage Black over Dustin Johnson. He made bogey on four straight holes on the back nine allowing Johnson to close the gap to one stroke.

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Johnson birdied on No. 15, but hit back-to-back bogeys at 16 and 17 to restore Koepka’s three-shot cushion.

Koepka finished with a 4-over 74 to win by 2 strokes to win the PGA Championship for the second straight year.

"I'm just glad I don't have to play any more holes," Koepka said. "That was a stressful round of golf. I'm glad to have this thing back in my hands."

Brooks Koepka, left, kisses his girlfriend Jena Sims after winning the PGA Championship golf tournament. (AP)

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The 29-year-old joins Tiger Woods as the only golfer to win the PGA in back-to-back years since the tournament went to stroke play in 1958. Koepka has also won back-to-back U.S. Opens.

Johnson, the No. 1 player in the world rankings, shot 69. It's the second straight major he's finished as runner-up. Johnson, who was second to Woods at the Masters last month, has finished second in all four majors.

"I gave it a run," Johnson said. "That's all you can ask for."

The Associated Press contributed to this report.