Dustin Johnson wins his first major championship despite earning a penalty after his ball rotated slightly on the fifth green. (Michael Madrid/Reuters)

They have been playing golf on this green planet for many centuries, and in that time many different elements have delivered golf balls from a resting state into motion, among them ash, persimmon, iron, titanium and the occasional leather FootJoy. In certain scenarios, wind, animal or act of God also have been known to cause a ball to move. But never before, until Sunday at Oakmont Country Club, had there been a documented case of a ball being moved by a ghost.

The question of what caused Dustin Johnson’s ball to rotate slightly backward on the fifth hole of the final round of the 116th U.S. Open is something that will haunt the sport — and is also ultimately unknowable, no matter how many slowed-down, blown-up replays are shown. It could have been Johnson’s putter. It could have been gravity as it worked its forces against blades of poa grass that were manipulated for days — triple-cut and rolled — to ensure maximum roll.

But in the wake of Sunday’s surreal ending to a grueling week — when Johnson made an otherwise brilliant and redemptive march to a four-shot victory in the U.S. Open, later reduced to a three-shot margin at 4-under-par 276 when the penalty was retroactively applied — golf fans may be asking another question: How could Johnson’s career-defining win, which came three days shy of his 32nd birthday, his first in a major championship following numerous awful failures, have to share the spotlight with the arcane nuances of the Rules of Golf?

“It’s a big monkey off my back,” said Johnson, whose previous 28 starts in majors had produced 11 top-10s and two runner-up finishes but no victories. “I feel a lot lighter.”

It’s too bad Johnson’s dominant performance — when he shot a closing 2-under 68 (officially, a 1-under 69) while almost everyone behind him was crashing and careening — will be linked forever with a mystifying and seemingly unnecessary rules controversy that, at best, makes the sport look silly and, at worst, could bring golf to an existential crisis, at a juncture when it is struggling to remain relevant in its post-Tiger iteration.

Only Johnson’s brilliant play down the stretch Sunday — when he tossed aside the distraction of the rules situation, as well as his own well-documented history of major championship heartbreak, to complete his victory — prevented this from exploding into a raging crisis. Imagine if he had finished just one shot clear of the field — or tied with the three golfers who wound up sharing second place at 1 under: Jim Furyk (66), Scott Piercy (69) and Shane Lowry (76).

For seven holes Sunday, Johnson lugged his singular burden around Oakmont, arguably the most difficult, penal track in championship golf — trying to hold off some of the world’s best golfers, under the most intense pressure the sport can produce, while knowing there could be a one-stroke penalty waiting for him afterward.

“I just went about my business,” he said. “I figured we’d deal with it when I was done.”

If he wanted to win, he apparently would have to beat the field by two.

And then, for perhaps the first time in his star-crossed career, it all started to fall into place for Johnson. Lowry — himself the victim of a one-shot penalty, self-imposed, two days earlier when his ball moved after he had addressed it — entered the round with a four-shot lead. It was all gone by the eighth hole, but for much of the day Lowry was Johnson’s closest pursuer — until three straight bogeys beginning at the 14th ended his hopes. He became the first player since Payne Stewart in 1998 to lose a U.S. Open after carrying a lead of four or more shots into the final round.

Piercy, a PGA Tour journeyman from Las Vegas, stalked the lead all day but bogeyed two of his final three holes.

The other players said they were told by rules officials that there was a rules issue regarding Johnson’s ball at the fifth green that could result in a penalty stroke.

When Johnson rolled in a 10-foot putt to save par on the 16th, he led the tournament by two — but really, given the one-shot penalty that appeared already to have been decided by that point, just one. If ever there was a point where Johnson would come undone, this was it.

By now, his litany of late stumbles in majors is well known: The final-round 80 he shot in the 2010 U.S. Open at Pebble Beach after carrying a three-shot lead into the final round. The penalty two months later for grounding his club in a bunker on the 72nd hole of the PGA Championship, costing him a spot in the playoff. And finally, his three-putt from 12 feet at last year’s U.S. Open at Chambers Bay to lose the tournament by a shot.

Critics thought Johnson had a problem with major-title pressure, that there was some character flaw, revealed on those championship Sundays, preventing him from getting it done. He figured it simply wasn’t his time.

“I think [Sunday’s win] is well deserved after everything I’ve been though in majors,” he said. “I’ve knocked on the door a bunch of times. To get that major win, it’s huge.”

When Johnson rolled in another par save on 17, while his opponents were going backward, the lead was three — but really two. And when he hit a perfect approach to 18 and sunk a five-foot birdie putt, he gave a slight fist-pump and accepted hugs and kisses from his fiancee, Paulina Gretzky, and their son, Tatum. The crowd, undoubtedly aware of a controversy that was erupting across social media all afternoon, roared and chanted, “D.J.! D.J.! D.J.!”

All that was left was the sorting out of the rules debacle. As Johnson was in the scorer’s tent, the penalty stroke was applied. By that point, with victory already in hand, there was little motivation for Johnson to fight it.

“I’m glad it didn’t matter” in the end, Johnson said. “Because that would have been bad.”

But the questions over it remain, among them: Why were Johnson’s actions at the fifth green cleared by both his playing partner, Lee Westwood, and a U.S. Golf Association official on the scene, only to have that clearance reevaluated and overruled? And why was it necessary to inform Johnson of an additional inquiry, which would not be resolved until after his round, as he stood on the 12th tee — as he was nursing a two-shot lead in one of four championships held every year that define a player’s legacy?

“We put him on notice,” Jeff Hall, the USGA’s managing director of rules and competition, said on Fox’s broadcast. “Based on what we saw, it could lead to a penalty stroke. We thought [telling him] was the only thing we could do. We think it was fair that we notify Dustin and give him the opportunity to see what we saw [on replay] at the end of the round.”

Someone with common sense also might ask: How could any action initiated by Johnson’s putter — which was behind or beside the ball at all times — have caused the ball to tilt backward?

The only answer: It couldn’t. Which means the list of culprits were reduced to two: gravity or a ghost. Johnson can’t do anything about gravity, but by Sunday evening, he had finally gotten rid of the ghost.