By DOUG FERGUSON AP Golf Writer

TROON, Scotland  — Xander Schauffele went from the most nerve-wracking putt of his career to the coolest walk toward an 18th green he ever imagined.

He won a nail-biter at the PGA Championship in May. He delivered a masterpiece Sunday in the British Open. Two different finishes, two different feelings.

One major conclusion.

Schauffele has more than enough game and all the confidence in the world to win the biggest championships. Questioned at the start of the season whether he could win a major, he now has two of them.

Schauffele closed with a 6-under 65 with a final round that ranks among the most memorable in British Open history, particularly the 31 on the back nine. It matched the best score of the week at Royal Troon with nothing less than the claret jug riding on the outcome.

He played bogey-free in a daunting wind and turned a two-shot deficit into a two-shot victory for his second major of the year.

It also gave the Americans a sweep of the four majors for the first time since 1982.

“It’s a dream come true to win two majors in one year,” Schauffele said. “It took me forever just to win one, and to have two now is something else.”

He won the PGA Championship at Valhalla by making a 6-foot birdie putt on the final hole for a 65. In a final round set up for high drama at Royal Troon — six players one shot behind, nine players separated by three shots — Schauffele made a tense Sunday look like a nice walk along the Irish Sea.

“I think winning the first one helped me a lot today on the back nine,” he said. “I had some feeling of calmness come through. It was very helpful on what has been one of the hardest back nines I’ve ever played in a tournament.”

It sure didn’t show. Standing on the 18th tee, Schauffele said he turned to caddie and longtime friend Austin Kaiser and told him that he had felt calm down the decisive back nine.

“He said he was about to puke,” Schauffele said.

In the 90-year history of four majors, Schauffele became the first player to win two majors in one season with a final-round 65. Jack Nicklaus is the only other player to do that in his career.

And he never looked more calm, oozing that cool California vibe even as the wind presented so much trouble at Royal Troon.

Schauffele pulled away with three birdies in a four-hole stretch early on the back nine to go from two shots behind to leading by as many as three.

He won by two shots over American Billy Horschel and Justin Rose, the 43-year-old from England who had to go through 36-hole qualifying just to get into the field. They were among four players who had at least a share of the lead at one point Sunday.

They just couldn’t keep up with Schauffele. No one could.

“He has a lot of horsepower,” Rose said. “He’s good with a wedge, he’s great with a putter, he hits the ball a long way, obviously his iron play is strong. So he’s got a lot of weapons out there. I think probably one of his most unappreciated ones is his mentality. He’s such a calm guy out there.

“I don’t know what he’s feeling, but he certainly makes it look very easy.”

Even with so many players in contention early, the engraver was able to get to work early on those 16 letters across the base of the silver claret jug.

Schauffele kept staring at golf’s oldest trophy in his press conference, looking forward to gazing at it in private, wondering what kind of drink to pour from it. He said he’d leave that up to his father, Stefan, who missed his son’s first major title and was blubbering on the phone with him.

As to where that final round ranks — Henrik Stenson shot 63 when he won his duel with Phil Mickelson at Royal Troon in 2016 — Schauffele left no doubt where it stood in his own career.

“At the very tip-top,” Schauffele said. “Best round I’ve played.”

Playing in the third-to-last group, he matched the round of the championship with a score that was just over eight shots better than the field average.

The final birdie was a pitch over a pot bunker to 4 feet on the par-5 16th. The grandstands at The Open are among the largest, lining both sides of the fairway as Schauffele walked through and soaked up the cheers.

“I got chills,” he said.

The 30-year-old from San Diego became the first player since Jordan Spieth in 2015 to win his first two majors in the same season. And he extended American dominance on this Scottish links as the seventh Open champion in the last eight visits to Royal Troon.

It was the 11th straight year for a first-time British Open champion, tying a tournament record.

Rose started one shot behind and closed with a 67. That was only good for second place. He had a chance to set a record by going the longest time between majors after his 2013 U.S. Open win.

“Gutted when I walked off the course and it hit me hard because I was so strong out there today,” Rose said. “Xander got it going. I hit a couple of really good putts that didn’t fall, and then suddenly that lead stretched. I left it all out there. I’m super proud of how I competed.”

Horschel, who started the final round with a one-shot lead in his bid to win his first major, dropped back around the turn and birdied his last three holes for a 68.

“I’m disappointed. I should feel disappointed. I had a chance to win a major,” Horschel said. “I just made a few too many mistakes today when I didn’t need to.”

The player Schauffele had to track down was Thriston Lawrence of South Africa, who birdied three of four holes to end the front nine with a 32.

Schauffele was two shots behind when it all changed so suddenly. Schauffele hit a wedge out of the left rough on the difficult 11th and judged it perfectly to 3 feet for birdie. He hit another wedge to 15 feet for birdie on the 13th, and capped his pivotal run with a 12-foot birdie putt on the par-3 14th.

Lawrence finally dropped a shot on the 12th and didn’t pick up any shots the rest of the day. He closed with a 68 and earned a small consolation — a trip to the Masters next April, his first time to Augusta National.

Scottie Scheffler, who got within one shot of the lead briefly on the front nine, lost his way with a three-putt from 6 feet for a double bogey on the ninth hole. Scheffler finished his round by topping a tee shot on the 18th and making another double bogey. The world’s No. 1 player closed with a 72 and tied for seventh.

He stuck around to share a hug with Schauffele, the two top players in golf. Schauffele was the only player this year to finish in the top 10 in all four majors.

He finished at 9-under 275 and earned $3.1 million, pushing him over $15 million for the season.

Schauffele went from the heaviest major trophy at the PGA Championship to the smallest and oldest, the famed claret jug.

“I just can’t wait to drink out of it,” he said, smiling as wide as ever.