The controversy revolved around whether Johnson should have been penalised when his ball moved on the fifth green.

After speaking with Johnson on the 12th tee, officials informed other players a decision would be made post-round.

A penalty stroke was added to Johnson's score but he won by three from Lowry, who had three bogeys from the 14th.

American Jim Furyk shot a four-under 66 to finish tied for second with compatriot Scott Piercy (69) and Lowry.

England's Lee Westwood, playing alongside Johnson, started the day on two under par but had a 10-over 80 to finish on eight over.

The United States Golf Association (USGA) later said they wanted Johnson to know of the potential one-shot penalty so he could play accordingly.

However, it led to confusion for players and fans alike, particularly when Lowry birdied the 12th to get to four under and nobody knew for sure whether he was level with, or one behind Johnson.

Northern Ireland's Rory McIlroy, who missed the cut, said on Twitter while the round was in progress that no penalty was warranted and called the USGA "amateur", adding that he "wouldn't hit another shot until the farce was rectified", while world number two Jordan Spieth called it "a joke".

What did Johnson do?

The American had been standing over his ball and made two practice putts. As he prepared to address the ball to make his putting swing, his ball moved slightly. Johnson stepped away saying that he had not addressed the ball - had he done so, he would have incurred a one-shot penalty.

Johnson's playing partner Westwood could clearly be heard saying that the American had not addressed the ball.

Johnson checked with a rules official, who was happy that there had been no infringement and he went on to par the hole.

Another rules official then approached Johnson on the 12th tee and, after a discussion, decided that they needed to review the television footage of the incident on the fifth green after he had completed his round because he could face a one-stroke penalty.

The penalty stroke was eventually upheld and Johnson, who replaces McIlroy as world number three after winning the US Open, signed for a one-under-par 69.

"It's definitely sweet to get that major championship," said the 31-year-old, who claimed he was not affected by the officials' intervention.

"At that point I just thought I'd deal with it when I'm done. I tried to block it out and not let it bother me.

"Who cares, it doesn't matter any more."

It will be some retribution for Johnson who had a 12-foot putt to win last year's US Open at Chambers Bay but took three to hand the title to Jordan Spieth.

He also missed out on a first major victory when he was handed a two-shot penalty for grounding his club in what the thought was wasteland but was ruled to be a bunker at the 2010 PGA Championship.

USGA defends actions

The USGA's director of rules Jeff Hall explained that after watching video of the incident he decided Johnson's actions "could have caused the ball to move".

Hall added: "The first time we had the opportunity to speak to Dustin was the 12th hole.

"We asked if there was some other reason the ball could have moved. He didn't state a reason.

"We decided not to review it with Dustin at the media tent on the 13th hole and instead wait till the end."

Lowry capitulates

During round two, Lowry, as professional golfers do, called a one-shot penalty on himself when his ball moved after he had addressed it on the putting surface of the 16th hole.

The Irishman refused to use the confusion surrounding Johnson's penalty as an excuse for his own demise.

He had already bogeyed four holes to drop to three under, two behind Johnson, by the time he learned of the potential penalty.

"It didn't affect me much at all," said Lowry.

"I credit Dustin for playing the way he played on the way in, having that hanging over him, because I probably would have wanted to know straight away if it was me.

"I just feel like I let it go. I'm very disappointed. The more I think about it the more upset I'm getting.

"It's going to be a tough few days. I led the US Open by four and I was tied for the lead with five holes to play. I am definitely good enough to win one of these."

The former world number one started the day five off the lead at two under par and with hopes of winning his first major.

However, a run of five bogeys and a double bogey in six holes from the second shattered his round and extended his unwanted run to 73 majors without a victory.

Westwood had just one birdie, on the par-four 17th, as he recorded a 10-over-par 80 to finish on eight over.

What about the rest?

Andrew Landry, the world number 624, who led after round one and stayed in contention all week, finally succumbed to the pressure in round four. Playing in the final group with Lowry the American carded an eight-over 78 to finish five over par.

Sergio Garcia threatened again at a major, reaching three under par on the 13th but a run of three successive bogeys ended his challenge and, like Westwood, he is still searching for a first win in one of golf's four big tournaments.

Furyk's four-under 66 was the lowest round of the day and catapulted the 46-year-old who won the 2003 title, up to a tie for second with Lowry and Piercy.

American Piercy opened with back-to-back birdies to get to two under and he picked up another shot on the 12th but he closed with bogeys on the 16th and 18th holes.

(BBC)