He toppled the mighty Tiger Woods.
Yang became the first Asian-born player to win a major Sunday with a stunning performance in the PGA Championship, memorable as much for his clutch shots as the player he beat.
Woods was 14-0 when he went into the final round of a major atop the leaderboard. He had not lost any tournament around the world in nine years when leading by two shots.
None of that mattered to Yang, a 37-year-old South Korean who hit the shots everyone expected from Woods. Leading by one on the final hole, Yang slayed golf's giant with a hybrid 3-iron that cleared the bunker and settled 12 feet from the cup.
Yang made the birdie putt and shouted with joy as he pumped his fist. That gave him a 2-under 70, and a three-shot victory when Woods missed yet another short par putt and shot 75.
"I tried to master the art of controlling my emotions throughout the small wins I had in my career," Yang said through his agent, Michael Yim. "I think it turned out quite well today."
It was the second time Woods has finished runner-up in the PGA Championship at Hazeltine, both times to a surprise winner. Seven years ago, he birdied the last four holes and came up one short of Rich Beem.
This time, Woods made one mistake after another over the last four holes, mostly with his putter.
"I did everything I needed to do, except for getting the ball in the hole," Woods said. "Just didn't make the putts when I needed to make them."
Yang was No. 110 in the world, his only victory on the PGA Tour coming in March at the Honda Classic, on a course across the street from headquarters of the PGA of America. He was best known for holding off Woods at the HSBC Champions in China three years ago.
This stage was far bigger. Yang was even better.
He took the lead for the first time all week by chipping in for eagle from about 20 yards short of the 14th green. And when it looked as though nerves were getting the best of him on a three-putt bogey at the 17th, he delivered his two most important shots.
Yang still had enough strength left to hoist his golf bag over his head, and later the 44-pound Wanamaker Trophy. After a long and tearful embrace with his wife, Young Ju Park, he walked across a bridge saluting thousands of fans who couldn't believe what they saw.
What a capper to this year in the majors.
Kenny Perry was poised to become the oldest Masters champion at 48 until Angel Cabrera beat him in a playoff. Phil Mickelson, reeling from his wife being diagnosed with breast cancer, was on the verge of finally winning the U.S. Open until Lucas Glover outplayed him over the final few holes. And just last month, 59-year-old Tom Watson was an 8-foot par putt away from winning the British Open, then lost in a playoff to Stewart Cink.
Woods losing a two-shot lead in the final round of a major? That was unthinkable - until a breezy afternoon at Hazeltine.
"I played well enough the entire week to win the championship," Woods said. "You have to make putts. I didn't do that. Today was a day that didn't happen."