Jordan Spieth celebrates with his caddie after holing a putt on the 18th green to win. (Andrew Boyers/Reuters)

The eccentric concoction known as golf has yielded Jean Van de Velde in Barry Burn at Carnoustie with his trousers rolled up, Roberto De Vicenzo signing an errant scorecard at the Masters, Seve Ballesteros finding his incorrigible ball giggling from under the front fender of a car, Phil Mickelson whacking a crucial drive off a hospitality tent and Dustin Johnson playing a U.S. Open back nine in ludicrous uncertainty about a possible penalty.

Still, that rich lore managed to annex a fresh wrinkle on a cockamamie Sunday at Royal Birkdale when Jordan Spieth, who won the 146th British Open at 12 under par by three shots over Matt Kuchar, did so partly by climbing a dune and then romping hopelessly around some sponsor trailers.

While Spieth racked up his third major title at age 23 and forged the fastest such progress in golfing life since Jack Nicklaus in 1963, that milestone does figure to bow in golf’s dimpled memory banks against the daffy path through which Spieth steered. His first claret jug will live on for what he did at No. 13, which then served to flatter him further because of his astounding blaze that followed and went birdie-eagle-birdie-birdie .

“I mean, I’m starving, you know,” he said afterward. “Today took about as much out of me as any day that I’ve ever played golf.”

He said he might have preferred the boredom of “17 pars and a birdie.”

Spieth celebrates his title. (Paul Childs/Reuters)

He said, “But there’s a lot of roads to get there.”

Along his fresh and nutty one, Spieth reached the 13th tee as a steady, steely technician from Dallas who blew one Masters in 2016 and had sprayed the Royal Birkdale course with uncompliant shots. He had made galleries keep reshaping themselves to allow room for his stray balls, three-putted thrice on the front nine, wretchedly missed a two-footer on No. 9 and frequented the ornery foliage. He had made four bogeys in 54 holes while building the three-shot lead he brought to the course yet four bogeys in nine holes toward a garish 37 going out, so as a result he and the 39-year-old Kuchar made the turn tied at 8 under par.

He had grimaced often and looked miserable more often.

Soon he also grabbed his head from both sides, just as his tee shot on No. 13 went so far right that it challenged the keen eyes of golf intellectuals trying to ascertain just how far it veered. Some settled for 100 yards, others 125. The hunt for the ball involved a blob of scurrying spectators and Spieth revealing creditable mountain-climbing skills by skipping up to the top of the top dune beneath the brooding clouds. It made for a lovely vista of the old links course on the Irish Sea but a lousy one for somebody who woke with a three-shot lead. From there, Spieth’s back-nine 32 that ensued would have seemed “crazy,” he said. “I would have thought, ‘How many eagles or holes-in-one did I make?’ ”

A 21-minute span of absurdity followed and featured Spieth playing marshal and directing galleries. The poor ball was unplayable. Rather than return to the tee, Spieth opted to back down the knoll, on the same line with the hole but further away, per the requirements of a drop. He wandered around like some straggler or lost jogger for a while, trying to discern the proper spot. He asked whether the practice range would be out of bounds and learned it wouldn’t. Halfway to forever later, he faced a blind third shot over the rude knoll. He thought it 270 yards. His caddie, Michael Greller, insisted on 230. Spieth opted for a 3-wood. Greller recommended a 3-iron. Spieth struck a 3-iron he disliked at first, but it wound up resting perkily in front and to the right of the green.

He chipped on expertly, made a towering bogey from eight feet and said later, “The putt on 13 was just massive.” At 7 under par, he trailed, but he trailed by only one against Kuchar, still seeking his first major title in 47 tries. And so Spieth adopted the role of the challenger, shortly after apologizing to Kuchar for the delay. Li Haotong, a 21-year-old from Shanghai, had shot a dazzling 63 to reach 6 under. A cavalry charge just below, including Rory McIlroy and U.S. Open champion Brooks Koepka, never menaced.

“Once he made that putt on 13,” Greller said, “there was just a different energy in him those last five holes,” as if, Greller also said, “He just said, ‘You know what? I know how to do this.’ ”

His very next shot was a gasping gem from the tee at par-3 No. 14, a 6-iron from 200 yards that merrily skipped just by the left edge of the hole to six feet and felt almost impossible to process given its precedents. He made that and retied the thing. His 48-foot eagle putt on No. 15 looked so cocksure that it rang true later when Spieth said: “Those three-footers were 10-footers to me, and all of a sudden the lid came off, and the 30-footers were two-footers to me.” Things had gotten giddy so abruptly that Spieth teased Greller across the green, “Go get it,” meaning the ball in the cup, and he led by one as Kuchar birdied almost anonymously.

Now Kuchar and his steady 69 got doused in the great closing wave that enabled Spieth’s carnival of a 69. On No. 16, Spieth birdied from 30 feet. On No. 17, he birdied from six after a chip that looked like all paradise. “It’s hard to explain,” Kuchar said. “It’s crushing. It hurts. And it’s an excitement and a thrill to have played well, put up a battle, put up a fight. . . . And to be this close, to taste it with five holes to go, it’s a hard one to sit back and take. However, thinking with five holes to play, I played the next four in 2 under par.”

That such prowess could go overwhelmed caused two-time major champion Zach Johnson to say of Spieth, “I can’t fathom it. Those are the intangibles and the things I just don’t understand. I’m not suggesting that I can’t do it. He just does it all the time.”

He had won the 2015 Masters in a romp, the 2015 U.S. Open by one shot when Dustin Johnson famously three-putted from 12 feet. Now he had done something that witnesses at a deeply respected course will try to fathom and describe for decades ahead. He had crammed all those occasions into one lunatic day, restored his scattered wits mid-round and then confessed that the goblins from the 2016 Masters had troubled him but that he had surmounted also them. “Closing today,” said this great American golfer arrived in full, “was extremely important for the way I look at myself.”