Hideki Matsuyama beat Kevin Na in a play-off to score a dramatic victory in the Memorial Tournament at Muirfield Village.
The Japanese star, who carded a closing three-under 69, looked to have blown victory in regulation time by going double bogey-bogey at 16 and 17.
But he gave himself a lifeline by forcing a play-off with a superb birdie at the closing hole to match Na's clubhouse total of 13-under.
And after Na had found water off the tee when the duo returned to 18, Matsuyama finally closed out his first PGA Tour win with a brave par after a brilliant up and down from left of the green after his approach had struck a spectator on the knee.
Na, who started his final round over two hours before the last pair teed off and seven shots off the pace, looked as if he would have to settle for the minor places despite a superb eight-under 64 to post 13-under.
But despite overnight leader Bubba Watson and Matsuyama both hitting 15-under on the back nine, they faltered badly over the closing holes to give Na renewed hope.
Watson improved to 13-under with an outward one-under 35 and added further birdies at 10 and 11 to reach 15-under.
But he bogeyed 14 after a loose tee-shot and then racked up a double bogey seven at the 15th after a wild drive out of bounds.
When Matsuyama birdied the par five 15th shortly after Watson had been forced to re-load back on the tee, it looked as if the young Japanese ace was in complete control.
But he immediately blew his two-shot lead by finding water off the tee at 16 and dropped back into a tie for the lead with Na, who immediately headed to the range to warm-up in the event of a play-off.
Matsuyama then bogeyed 17 to leave Na in front on his own but just when it appeared he'd thrown away his victory chance the 22-year-old hit a stunning second to 18 and rolled in a five-foot birdie putt to force a play-off.
Watson could have joined them with a three at the last but his towering six-iron ran off the back of the green and he couldn't hole his curling chip shot.
Matsuyama was forced to tee off with his 3-wood in the play-off after semi-slamming his driver into the ground and snapping it on the final hole of regulation play when it looked as if he'd found rough (his ball actually rolled back onto the fairway).
It appeared it may have cost him when he drove into a fairway bunker when a driver may have cleared it but Na hit his tee-shot left into water.
After a penalty drop, Na's third finished in thick rough right of the green and his fourth finished 12 feet away.
But before Na got the chance to putt, Matsuyama floated a chip onto the green and nailed his par effort from 10 feet to secure a rollercoaster victory.
World No 1 Adam Scott, who partnered Matsuyama in the final round, finished in a tie for fourth with Chris Kirk but, like fellow Green Jacket Watson, was left to rue what might have been.
Scott birdied the 11th from 25 feet to get to 14-under but doubled the 12th and had a hat-trick of bogeys from the 14th to slip back to 10-under.
Rory McIlroy ended a topsy-turvy week with a level par 72 which featured five birdies and five bogeys.
The Northern Irishman, who won last week's BMW PGA Championship at Wentworth, held a three-shot lead after a stunning opening round 63 but fell back into the pack with a six-over 78.