By Darci Miller | June 19, 2016, 8:14 p.m. (ET)
Dustin Johnson plays his second shot on the seventh hole at the U.S. Open at Oakmont Country Club on June 18, 2016 in Oakmont, Penn.

On a day that could have ended in disaster, Dustin Johnson remained cool through controversy.

On the fifth hole of the final round of the U.S. Open, as Johnson lined up a putt, his ball moved slightly, meaning he would be assessed a penalty. He was absolved of any fault, however, and play continued. At the 12th hole, officials amended the decision and announced that they would review the play after the final round was completed. Johnson was forced to complete the remainder of the round with the specter of a potential penalty hanging over his head. If awarded, Johnson would be penalized one stroke.

But Johnson left nothing to chance. Entering the final round at a four-stroke deficit, he continuously made up ground. He shot 1-under 69 on the day, finishing at -4 with a score of 276. With his closest competitors at -1, he ensured that any potential penalty would not be a factor. Countrymen Jim Furyk and Scott Piercy tied with Shane Lowry of Ireland for second place.

“I just tried to focus on what I was doing and not think about the penalty stroke,” Johnson said after receiving the trophy. “Just play golf.”

Johnson trailed Lowry by two strokes after the fifth hole but found himself with a two-stroke lead after 13. That lead shrunk to one after the 14th hole. But as others were plagued with sloppy play, Johnson finished strong.

Amidst “USA” chants from the crowd, he approached the 18th and final hole with a three-shot lead. After a 6-iron dubbed “the shot of his life,” he birdied with his final putt – only the second birdie of the day on the 18th hole – to maintain it.

 “It was a very nice way to finish,” Johnson said. “It might be one of the best shots I’ve ever hit, especially under the circumstances.”

The 2016 U.S. Open is Johnson’s first major championship win. Ranked No. 6 in the world, he had previously finished in a tie for second place at the 2015 U.S. Open and the 2011 Open Championship. He had two other top-10 finishes in Masters Tournaments in 2015 and is currently ranked 7th on the PGA Tour.

The U.S. Open was the final major championship before the Rio 2016 Olympic Games, where golf will be making its first Olympic appearance since 1904. The Olympic field will be determined on July 11 based on the Olympic Golf Rankings. The top four U.S. men will qualify for the Olympic team; as of June 13, Johnson would be the fourth qualifier, along with Jordan Spieth, Bubba Watson and Rickie Fowler.