OAKMONT, Pa. — J.J. Spaun turned a sloppy mess of a U.S. Open at wet and nasty Oakmont into a thing of beauty at the end Sunday with two stunning shots that carried him to his first major championship.

First came his driver on the 314-yard 17th hole onto the green for a birdie that gave him the lead. Needing two putts from 65 feet on the 18th to win, he finished his storybook Open by holing the longest putt all week at Oakmont for birdie and a 2-over 72.

That made him the only player to finish the tournament under par at 1-under 279.

It gave him a two-shot victory over Robert MacIntyre of Scotland.

And it made Spaun, the 36-year-old Californian who resembles the late Pittsburgh Steelers great Franco Harris, a major champion in only his second U.S. Open.

“I never thought I would be here holding this trophy,” said Spaun, who finished last year at No. 119 in the world with only one PGA Tour title in his career.“I always had aspirations and dreams. I never knew what my ceiling was. I’m just trying to be the best golfer I can be.”

It was calamity for so many others. Sam Burns had a two-shot lead going to the 11th tee, made a double bogey from a divot in the first cut and from a lie in the fairway so wet he thought he deserved relief. He shot 78.

Adam Scott, trying to become the first player to go more than 11 years between major titles, was tied for the lead with five holes to play. One of the best drivers could no longer find the fairway. He played them in 5 over and shot 79.

Carlos Ortiz and Tyrrell Hatton also slashed away in slushy lies, all making mistakes that cost them a chance to survive this beast of day.

The rain that put Oakmont on the edge of being unplayable might have saved Spaun.

One shot behind at the start of the day, he opened with five bogeys in six holes with some horrific breaks, none worse than hitting the pin on the second hole and seeing it spin back to the fairway. And then came a rain delay of 1 hour, 37 minutes.

Remarkably, he made only one bogey the rest of the way.

But oh, that finish.

MacIntyre, the 28-year-old from Oban toughened by the Scottish game of Shinty, became the new target. He also struggled at the start and fell nine shots behind at one point. But he birdied the 17th and split the fairway on the 18th for a key par, a 68 and the clubhouse lead.

Three groups later, Spaun delivered what looked like the winner, a powerful fade that rolled onto the green like a putt and settled 18 feet behind the cup.

And then the final putt — no one made a longer one all week. He was helped by Viktor Hovland being on the same line and going first. Spaun rapped it through the soaked turf, walked to the left to watch it break right toward the hole and watched it dropped as thousands of rain-soaked spectators erupted.