DUBLIN, Ohio (AP) — Collin Morikawa figured his tournament was over if he didn’t make a 5-foot par putt on the 15th hole at Muirfield Village.

He couldn’t have imagined all the fun was just starting.

Still three shots behind Justin Thomas with three holes to play, Morikawa made only one birdie and it was enough for a 6-under 66 to force a playoff.

The three times he played the 18th hole, he twice could only watch as Thomas had 10-foot putts for the win.

The other time, Morikawa had to make a 25-foot putt to keep playing.

The only dull moment Sunday at the Workday Charity Open was the end, when Morikawa took two putts for par from just inside 10 feet to beat Thomas on the third playoff hole and win for the second time in his career.

“Amazing,” Morikawa said when asked how he would sum up the day to someone who only saw the result.

That covered a lot of territory.

Morikawa never looked like the winner until it was over.

Thomas had 10 straight one-putt greens, the last one a 25-foot eagle putt on the par-5 15th for the three-shot lead with three holes to play. And while he made two bogeys for a 69 that allowed for a playoff, he had reason to think it was over when he made a 50-foot birdie putt from the back of the 18th green.

“I never assumed it was over,” Thomas said. “Percentages would say that it heavily is close to being that way. … I just tried to keep my head down and think he’s going to make it, but hoping he’s not, selfishly, but he did.”

Thomas missed a 10-footer for par in regulation, and a putt close to that same line for birdie on the second extra hole. He was done in by a tee shot on No. 10 that wound up in the rough behind a tree, forcing him to pitch out 102 yards short of the green. He missed his 15-foot par putt, leading to Morikawa’s two-putt par and the win.

It was a wild ride for Thomas, too. He started with a two-shot lead, trailed by three after just five holes, made four straight birdies and was ahead by three shots 10 holes later, and ultimately lost in a playoff.

“It’s completely unacceptable to give up a three-shot lead with three to go,” Thomas said. “I’m upset, I’m disappointed in myself. But at the end of the day it’s over with now, and I just need to take some time this afternoon and tonight to build on it and figure out what I can do better going into next week.”

They return in four days for the Memorial on a Muirfield Village course expected to be as fast as a U.S. Open.

This was a big win for the 23-year-old Morikawa, who in his 13 months since graduating from Cal already has established a reputation for a high level of consistency. His only victory was at an opposite-field event last summer. He beat a field at the Workday Charity Open that featured five of the top 10 in the world.