(Reuters) - Kodai Ichihara made an up-and-down birdie from 100 yards at the final hole to win the Dunlop Phoenix by one stroke as an out-of-sorts Brooks Koepka finished 12th in Miyazaki on Sunday.
World number 425 Ichihara rattled home with an eight-under-par 63, finishing in style by almost holing his third shot at the par-five 18th.
He sank the short birdie putt and secured a surprise victory when fellow Japanese Mikumu Horikawa bogeyed the par-five 18th minutes later.
Horikawa made a complete mess of the last, finding a fairway bunker with his tee shot, and a greenside bunker with his third. He missed a 12-foot putt that would have forced a playoff.
Ichihara was on the range preparing for a playoff at Miyazaki Country Club when word filtered through that he had won for the second time this year on the Japan Tour.
He started the day five strokes behind Horikawa, but vaulted into contention with three early birdies, followed by an eagle at the par-four ninth.
Ichihara finished at 15-under 269, while overnight leader Horikawa carded 69 for 14-under.
Australian Brendan Jones (68) was two shots behind in third place. He missed a short birdie putt at the last.
World number one Brooks Koepka, a double major winner in 2018, never looked like making it a hat-trick of victories at the event after starting the final round five shots from the lead.
"I've probably hit it the worst I've hit all year
today, and I didn't make any putts," the American said after a 69 that left him six strokes off the pace.
"It’s hard to really expect anything different.
"The fans here are great, so polite, so supportive. It’s fun to play in front of them. Unfortunately, I just couldn’t give them anything to get excited about this week."
(Reporting by Andrew Both Tokyo, editing by Amlan Chakraborty)