One of the last people who would have predicted Jimmy Walker’s win in the PGA Championship at Baltusrol was the man himself.

Though Walker felt some improvement last week at the Canadian Open, he’d struggled much of the year, particularly in the majors. And he’d never really come close to winning in golf’s biggest events.

So after a pressure-packed par on the final hole gave Walker a one-stroke win over defending champion Jason Day on Sunday, he was somewhat surprised and plenty relieved.

“I wouldn’t have called this, but it’s huge,” Walker said. “It’s nice to get in the position and keep the hammer down and keep making birdies and playing well.”

Walker played so well in one of the strangest PGA Championships in recent memory that he led wire to wire. And after Day eagled 18 to close within one stroke, Walker played a solid third shot from the rough near the 18th green, then two-putted in near darkness for his first major title.

“It’s surreal,” said Walker, whose 67 put him at 14-under-par 266. “It feels sweet. It’s amazing. I haven’t been playing all that well and it felt like some things clicked last week, and brought it in this week and been thinking a little better on the golf course. I’m having a hard time putting words to it right now.”

Day, trying to join Tiger Woods as the only back-to-back winners of the PGA Championship in stroke play, didn’t have any such trouble.

“One guy this week was better than me,” Day said. “I know exactly how Jimmy feels, because I did exactly that last year. So it was actually quite nice to be able to see him celebrate with his family and friends there. … He’s a very deserving winner.”

A winner who came out of the blue even though Walker is ranked 48th in the world and has five PGA Tour victories. He missed the cut in the U.S. and British Opens this year after a tie for 29th at the Masters. In fact, he didn’t make the weekend in four of his last eight tournaments.

But he was superb this week to get the Wanamaker Trophy. He played the final 28 holes without a bogey, and survived in the tightest of spots during Sunday’s 36-hole finish — the first in this event since Jim Turnesa won the 1952 PGA Championship in a 36-hole match.

Walker’s win completed a sweep of first-time major winners: Henrik Stenson at the British Open, Dustin Johnson at the U.S. Open, and Danny Willett at the Masters.

Walker also moved from No. 29 to No. 4 in the Ryder Cup standings, all but assuring him a spot on the team.

He is a late bloomer who has received as much attention in recent years for his astrophotography, with some of his work recognized by NASA. He met his caddie, Andy Sanders, right here 16 years ago during a practice round at the 10th tee on the Upper Course at the U.S. Amateur. Sanders, who has multiple sclerosis, received a huge hug from Walker after the final putt fell.

That the tournament finished on time was stunning considering the inclement weather and the PGA’s decision on Saturday not to go to threesomes nor to have the twosomes tee off on Nos. 1 and 10. Day would have liked the opportunity to play with Walker in the last pairing of the final round, but the same duos played together in the third and fourth rounds, regardless of score.

British Open champion Henrik Stenson, trying to join Ben Hogan as the only players to win back-to-back majors at age 40, finally faded away with a double bogey on the 15th hole.

“It was a long day. I never felt like I brought my ‘A’ game,” said Stenson, who started the final round two shots behind and closed with a 71. “I think I hit more poor shots in the two rounds today than in the previous six or seven rounds combined.”

Brooks Koepka, playing for the first time since he pulled out of the Bridgestone Invitational one month ago because of an ankle injury, didn’t make a birdie until the 15th hole and closed with a 70 to tie for fourth. He also is in solid position for the U.S. Ryder Cup squad.

Daniel Summerhays birdied three of his last four holes for a 66 to finish alone in third, earning him his first trip to the Masters next year.

Robert Streb, whose 63 on Friday tied the lowest round in any major, shot 72 and 69 to finish six strokes back.

Jordan Spieth, last year’s sensation on tour with two major wins and Player of the Year honors, was blanked in the big tournaments this season. He shot 69 and 68 Sunday and was at 6 under.

Walker already was looking ahead after his exhausting win.

“I saw Davis this week,” Walker said of U.S. captain Davis Love, “and I told him, ‘Man, I’d love to be on your team.’”

Another goal accomplished.