TROON, Scotland — Phil Mickelson can count the heartaches and disappointments. He can second-guess himself for his shots on the 18th hole at Winged Foot in 2006 or his poor wedge play down the stretch at Merion in 2013.

In his mind, those were U.S. Open titles that he frittered away.

On Sunday in the British Open at Royal Troon, Mickelson shot a bogey-free 6-under-par 65 and lost to the round of a lifetime by someone else.

Henrik Stenson's 8-under 63 tied Johnny Miller for the lowest final round in major championship history. The Swede's winning total of 20-under 264 was the lowest 72-hole score ever in the majors.

The two-man duel was scintillating stuff, a back-and-forth match that will go down as among the greatest in history. Stenson didn't get the lead for good until the 14th hole, and then he seized the claret jug emphatically with three straight birdies.

Yet Mickelson, 46, was going to need time to process whether all that great play meant much since he lost, though his previous five major wins will no doubt be of some long-term comfort.

Mickelson's 17-under total would have won all but two Opens over the past century. In the first round, if his birdie putt on the 18th hole had not spun out of the cup, he would be the first player in history to shoot 62 in a major.

“You know,” he reflected, “it's not like I have decades left of opportunities to win majors, so each one means a lot to me. And I put in my best performance today. Played close to flawless golf and was beat.”

The thought Mickelson said he was left with: “What do I need to do?”

Maybe birdie every hole. Mickelson managed four birdies and an eagle Sunday, but Stenson overpowered him with 10 birdies.

Stenson, 40 and ranked No. 6 in the world, became the first Scandinavian to win a major because he enjoyed the usual precision with his irons while finding a putting prowess he'd never displayed before. Moreover, he showed a resolve that he'd never tapped into this deeply.

“It's not something you want to run around and shout, but I felt like this was going to be my turn,” Stenson said. “I knew I was going to have to battle back if it wasn't, but I think that was the extra self-belief that made me go all the way this week.”

In conditions that were tough and windy early, but turned benign and sunny on the back nine, Stenson and Mickelson lapped the field. J.B. Holmes closed with a 69 and finished in third, 14 strokes behind Stenson.

The match was being compared to the 1977 British Open showdown between Jack Nicklaus and Tom Watson at Turnberry, dubbed “The Duel in the Sun.” Watson prevailed by a shot over Nicklaus and 11 over third-place Hubert Green.

“I was thinking about that,” Mickelson said with a slight smile. “I know I wanted to be more of Tom in that case than Jack.”

Down by one shot at the outset, Mickelson immediately reversed the score when he hit his approach to within 1 foot at No. 1 and Stenson three-putted. Over the next 10 holes, they halved with par only twice while combining to score nine birdies, an eagle and one bogey.

They traded birdies at No. 10, but Stenson fell into a tie when he bogeyed 11 with a three-putt. It stayed that way until Stenson made an 18-foot birdie putt at 14.

“That stung,” Mickelson said.

Then came the crushing blow — Stenson putting from off the green, at least 40 feet, and making birdie at 15.

“Absolute bomb,” Stenson said.

Mickelson had a chance to tie when he gave himself an eagle putt at 16, but his ball broke off an inch from the target and hung on the edge. He had to settle for birdie, and Stenson matched him with a 5-foot birdie.

“I really thought I made eagle on 16,” Mickelson said. “I don't know how that eagle putt missed. … But it seems there have been a couple of putts like that this week.”

He smiled, obviously referring to the Thursday putt on 18 for 62.

It was that kind of week for Mickelson: Being great just wasn't good enough.

tod.leonard@sduniontribune.com