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Brooks Koepka of the United States poses with the Wanamaker Trophy on the 18th green after winning the 2018 PGA Championship with a score of -16 at Bellerive Country Club on August 12, 2018 in St Louis, Missouri. Richard Heathcote/Getty Images

In a thrilling PGA Championship on Sunday at Bellerive Country Club in St. Louis, U.S. Open champion Brooks Koepka shot a second straight 4-under 66 to close out a two-shot win at 16 under for his third major title.

The 28-year-old fought off a late charge from Adam Scott, who finished third after a bogey on the 18th hole.

Koepka wasn't sure he was going to compete in the major due to a left wrist injury.

“It’s mind-boggling,” Koepka said. “To go from not even sure to if I was going to be able to play this year to this is truly incredible.”

It was the second-place finisher, Tiger Woods, who also put on a show. Woods on Sunday shot a 6-under 64, the best fourth round of his career, to finish the tournament 14-under 266. The 14-under was Woods' best career score in a losing effort. His fourth round included eight consecutive birdies.

Woods finished the third round four shots behind Koepka but quickly made up ground Sunday, going three-under through his first nine holes.

Woods was among the first competitors to congratulate Koepka.

"What [Koepka] is doing back there is tough to beat," said Woods. "When a guy hits a 340 [yard shot] down the middle -- that's tough."

Koepka was quick to praise Woods, as well.

"Other than me, my team, everybody was rooting for Tiger," Koepka said. "It kind of pushes you to step up your game."

After some impressive performances in 2018, Woods again told reporters that he was appreciative to return to the tour after prolonged inactivity due to injury.

"It's been a hell of a process, for sure," said Woods.

Woods praised the crowd for their positivity and for being respectful. He called it a "true pleasure" to play at Bellerive.

"The energy was incredible," Woods said. "There was no negative comments. No one was jeering. No one was making snide remarks. Everyone was very positive."

By finishing second, Woods improved to 11th in the Ryder Cup standings.