This is how it happened at Royal Troon on Sunday, how it happened at Troon and to Phil Mickelson, on a day when Phil tried to do what Arnold Palmer once did on this same golf course and win his sixth major championship. Phil ran into the most dangerous opponent in the world in Henrik Stenson like he was running into a straight right hand. He ran into an athlete having the day of his life.

"I felt it was my time," Stenson said when it was over, and the Claret Jug was in his hands and he had heard himself called "the champion golfer of the year."

In the history of golf, there has never been a better final round than the one Stenson played on Sunday to win his first major at the age of 40. There was one just as good once, by Johnny Miller, at old Oakmont in 1973, on the day when Miller shot an 8-under 63 and passed what felt like half the field and won the U.S. Open. Miller didn't play better than Stenson, who no longer is the best golfer without a major, did at Troon.

When Miller won the Open, John Schlee finished second. When Stenson shot the round he did, and had his ball fall into the side of the cup the way Mickelson's did not on Thursday when he had a chance at 62, he beat Phil Mickelson, a Hall of Famer, on a day when Mickelson could have beaten anybody in this world except the guy he was playing with. When Mickelson won the British Open at Muirfield three years ago, he played pretty much the way he did on Sunday at Troon. Mickelson shot 66 that day in 2013. Was 5-under. Won his fifth major. On Sunday, he shot 65, 6-under. And lost to Stenson.

So this is what really happened to Mickelson in Scotland this week, as he tried to win a major championship at 46 the way Jack Nicklaus was 46 when he won the Masters in 1986: He shot a 63 in the first round and came within one-half a roll of his golf ball from shooting 62. He shot a 65 in the last round. And lost by three strokes in the end, because Stenson birdied the last. And guess what? Stenson had a shorter birdie putt on No. 17 and barely missed that.

There was a point during the broadcast on NBC when David Feherty said that Stenson hadn't missed the face of his club all day. Feherty paused then and said, "All day."

All day, on the day of his life.

Stenson had waited a long time for this. He is 40. There have been golfers who won their first major after the age of 40. Not a lot of them. Darren Clarke did it once at the British Open. But no one ever did it like this, standing in there against everything Mickelson threw at him, having the lead and then losing it and then getting it back and losing it again.

There was a touch of wonder in Mickelson's voice when he said to NBC's Steve Sands, "He made 10 birdies." A few minutes later he said, "I threw everything I had at him I could."

He did. Oh man, did he ever. Phil had to think, even when they both made the turn at 4-under, that he was the one on the day of his life. Maybe he even had another 63 in him. It was that kind of game of one-on-one they were playing against each other, as if the rest of the field were playing for the First Flight championship at your country club.

And this was a movie I had seen before, with my own eyes at the British Open of 1977 at Turnberry, Tom Watson against Jack Nicklaus in what was called the "Duel in the Sun." On that weekend in 1977, Nicklaus shot 65-66. It wasn't good enough because Watson shot 65-65. Watson ended up at 12-under par. Nicklaus ended up at 11-under par. The next best score was Hubert Green, at 1-under, followed by Lee Trevino, a two-time British Open champ himself. Trevino finished at even-par that year, a dozen shots behind Watson, a fast 11 behind his old nemesis, Nicklaus. Watson vs. Nicklaus was the closest thing to a golf game of H-O-R-S-E I have ever seen in my life. Or golf has ever seen.

On the last hole, Nicklaus pushed a drive right into some junk. It looked like he had no chance to get the ball to the green. But he was Jack. Somehow he gouged an 8-iron to the front part of the 18th green at the Ailsa course. And what does Watson do on the same hole, protecting his one-shot lead? He knocks a 7-iron to about two feet.

From behind the 18th green, Trevino yelled, "Let the big dog eat!" It should have finally been over. Only it wasn't over. Because Nicklaus proceeded to knock in a 35-foot putt for birdie. I was standing with the great Dan Jenkins at the back of the green, and when Nicklaus' putt somehow found the hole, Dan quietly said, "Greatest curtain call in history."

It was like that between Stenson and Mickelson at Troon on Sunday, stroke play feeling like match play. Or maybe like some heavyweight championship fight. You kept waiting for Stenson to break, even though he thought it was his time. You kept waiting for him to show the weight of his long journey to a moment like this. Only he did not break, on the day when he finally broke through. He kept finding fairways. He kept hitting shots on the clubface, all the way to the clubhouse.

He got to 17, a tough par-3 when there is even the hint of wind. He knocked the ball close again. Mickelson missed to the left, his ball rolling down away from the flagstick, what seemed like his last chance to cut into what had become a two-stroke lead rolling away with it. He hit a bump chip that stopped too far short of the hole. But it was almost as if Mickelson refused to make a bogey. Not here. Not the way they'd both been playing. He made the putt. Stenson missed his birdie putt. So his lead was still two on the 18th tee.

He nearly hit his favorite club, a 3-wood, into a bunker. Who knows what happens if he does? But the ball stopped short. Sometimes you have to be lucky as well as good. Or great, in his case. He gave himself one last birdie chance. Mickelson's long birdie attempt came up short. Stenson hit this swinging right-to-lefter that seemed as if it were about to hang on the edge. It didn't. He had his 63. He was 20-under. One more birdie. No. 10. A perfect 10. Phil Mickelson was up against him on Sunday. He was up against that. He had some day, too. Just not Henrik Stenson's.

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Mike Lupica is a columnist for Sports on Earth and the New York Daily News. Read his full bio here. Follow him on Twitter @MikeLupica.