ROCHESTER, N.Y. -- In the final round of the 105th PGA Championship at Oak Hill Country Club on Sunday, Brooks Koepka seemed determined to step on the gas early.

He had three straight birdies in the first four holes to open up a 4-shot lead over Norway's Viktor Hovland and Canada's Corey Conners. Then he held on when Hovland and Scottie Scheffler, two of the best players in the world, made their moves on the back nine.

Koepka carded a 3-under 67 in the final round Sunday and was 9 under over 72 holes to win the Wanamaker Trophy for the third time, beating Scheffler and Hovland by 2 strokes.

Koepka had warned us: Whatever was going on between his ears heading into Sunday at the Masters in April would never be muttered in his mind again. Koepka had a 2-shot lead heading into the final round at Augusta National Golf Club. He shot 3-over 75 in the final 18 holes and lost to Spain's Jon Rahm by 4 strokes.

Even Koepka, one of the most confident golfers in the world, acknowledged this week that he choked while trying to win his first green jacket.

"I promise I won't show up like [the Masters] tomorrow," Koepka said Saturday. "I won't have that thought process. It'll be completely different and we'll see where it puts me."

Hovland had stayed within striking distance of Koepka until the par-4 16th hole, where he hit his drive into a fairway bunker. His second shot became embedded into the bunker's face, leading to a double-bogey and ending his chances. Koepka had a birdie on the hole to take a 4-shot lead.

It is a historic victory for Koepka and the LIV Golf League, the Saudi Arabian-financed circuit that reportedly paid him $100 million in guaranteed earnings to lure him away from the PGA Tour in June. Koepka is the first LIV Golf League player to win a major championship.

"He's been knocking on the door a lot and he's been playing some really good golf," said Phil Mickelson, another LIV Golf League captain. "And I think we're all kind of expecting that to happen. ... He's been working really hard and it's good to see him playing well."

Over four days at one of the most difficult golf courses in the world, Koepka reaffirmed his position as perhaps the best major championship player of his era. He claimed his third PGA Championship title -- he also won at Bellerive Country Club outside St. Louis in 2018 and Bethpage Black in Farmingdale, New York, the next year. He becomes only the third player to win the PGA Championship at least three times after it became a stroke-play event in 1958; Jack Nicklaus (five) and Tiger Woods (four) were the others.

Koepka, 33, also won the U.S. Open in back-to-back years, at Erin Hills in Wisconsin in 2017 and at Shinnecock Hills Golf Club in New York in 2018. According to Justin Ray of the Twenty First Group, he becomes only the seventh player since 1950 to win five majors before age 34: Woods, Nicklaus, Arnold Palmer, Seve Ballesteros, Gary Player and Tom Watson also did it.

From 2015 through 2018, Koepka had a final-round scoring average of 68.9 in the majors. Nobody was better on golf's biggest stages.

Koepka hasn't said it, but we can assume that he believed he played too conservatively in the final round of the Masters. He came out firing at Oak Hill Country Club's pins Sunday after rain from the day before softened the greens.

Koepka made par on the first hole and then carded three straight birdies to grab a 4-shot lead. According to ESPN Stats & Information, Koepka was the first 54-hole leader at a major in the past 20 years to start 3 under or better in his first four holes of the final round.

With the pin only 3 feet off the front and right on the par-4 second, Koepka hit his approach shot to 4½ feet. On the par-3 third, his tee shot stopped four feet from the hole, despite a stiff crosswind. He sank a 9-footer for birdie on the fourth. Koepka was cruising.

"When he gets in contention, he's like a shark when there's blood in the water," Rahm said during CBS Sports' broadcast Sunday.

Then, just like that, Koepka lost all of his momentum. After Hovland posted consecutive birdies on Nos. 4 and 5 and cut his deficit to 2 strokes, Koepka made his first big mistake. On the par-4, 481-yard sixth hole, he sliced his drive far to the right. His ball crossed over a native area and ended up in the deep rough left of the seventh fairway. Koepka was forced to take a drop and knocked his third shot onto the green. Hovland had a nice up-and-down out of a greenside bunker to save par on No. 6 and cut Koepka's lead to 1 shot.

Koepka extended his lead to 2 strokes with another birdie on the par-4 10th. Kopeka and Hovland traded blows on the back nine. Koepka added birdies on Nos. 12 and 14. Hovland had back-to-back birdies on Nos. 13 and 14. Then Hovland made the big mistake on No. 16.

It was redemption for Koepka, who acknowledged at the Masters that he might not have jumped to LIV Golf if his body had been in better shape a year ago. At the time, he was still recovering from a dislocated right knee. Koepka said he fell at home and tried to pop his kneecap back into place. In the process, he shattered his kneecap and ruptured his medial patellofemoral ligament.

"You know, my leg was sideways and out," Koepka said at the Masters two months ago. "My foot was turned out, and when I snapped it back in because the kneecap had already shattered, it went in pretty good. It went in a lot easier."

During the Netflix series "Full Swing," Koepka seemed bruised and battered, wondering aloud if he could compete with the likes of Scheffler and other young stars any longer.

"I'll be honest with you, I can't compete with these guys, week in, week out" Koepka said during a dinner at the 2022 Masters, where he missed the cut. "A guy like Scottie, he can shoot 63 every day. I don't know."

After posting a second consecutive 4-under 66 on Saturday, Koepka acknowledged that he "came back too soon and played for too long" and developed bad habits.

Koepka is healthy now and he's performing like one of the best golfers in the world again. On Sunday, he might have earned the biggest victory in LIV Golf's brief history.