Brooks Koepka stared down rampaging Adam Scott and Tiger Woods and simply did not blink.
The American won his third major championship in 14 months when he carded an ice-cool four-under-par 66 at Bellerive Country Club to win by two strokes.
Koepka, already with two US Opens under his belt, watched as the power duo rose from a huge pack at halfway in a pulsating final round, then did nothing more than play his final 12 holes in five under par.
Woods, for the second major in a row, looked the winner near the turn when he closed within one en route to a stunning 64.
Then Queenslander Scott caught fire with five birdies in seven holes on his own way to an impressive 67 despite a bogey on the last that dropped him to third, one behind Woods.
But all that those runs did seemingly was to steel the 28-year-old Koepka to become just the 20th player to have won two majors in the same year.
With so many permutations still on the cards, Koepka stroke a 4m birdie dead centre on the 15th, then hit a laser four-iron to 2m on the 225m par-three 16th to take what would be the winning lead.
Nervelessly, he then ripped two huge drives down the 17th and 18th holes to effectively ensure his spot in history as just the fifth player to win both the US Open and PGA Championship in the same season, all on the back of a wrist injury last year that threatened his career.
“To go from not sure if I’m going to play again … it’s mind-boggling,” Koepka said.
“I don’t have answer for it, but I’m glad it happened.”
Asked how he remained so calm and has been the dominant player in the past six majors, Koepka replied: “My focus, I need to take it out on the regular tour events, too.
“For some reason the majors get my attention … I always do a pretty good job.
“The beginning of the back nine I could hear all the roars. When they made runs, it got loud. It was enjoyable.
“It’s truly incredible.”
Scott, who’d only had one top-10 finish in the past 14 months, had mixed emotions after his best showing of the year.
“I was feeling really good out there, especially as the back nine got going … everyone got going around the turn and there were a lot of roars,” the 38-year-old Australian said.
“But I just missed putts on 14 and 15 and then Brooks made them and my momentum was gone.
“Then I didn’t play the last two holes too well.
“I had high hopes today, especially with 4-5 to play today and being tied with Brooks, but I’m definitely playing a lot better and moving in the right direction at a good time of the year.”
Woods was the Tiger of old, despite hitting only five fairways, making key iron shots and nailing birdie putts to incite the huge crowd roaring his name.
“I played hard, it was a bit of a struggle with my game, I was just hanging in,” Woods said after his lowest final-round score in a major championship.
“But I made a bit of a run … just hung in there with my mind … and came up a couple of shots short.”
Jason Day couldn’t find any final-round magic and carded a flat 71 to finish T19 at seven under to be the next best Aussie.
Cameron Smith played his second great round in three days to card a 66 and leapfrog up to T56 at one under.
Marc Leishman, one of just 11 players to make the cut at all four majors this year, fired a 71 to finish two over and T71.