Schauffele closed with a final-round four-under-par 67 to strike gold at 18-under by a stroke from South African-turned-Slovakian Rory Sabbatini, who snatched silver with an Olympic-record 61 on Sunday.

Taiwan's C.T. Pan survived an epic seven-man playoff to nab bronze after shooting an eight-under 63 playing alongside Sabbatini in one of the tightest finishes in golf history.

Japan's big home hope Hideki Matsuyama (69), Irish superstar Rory McIlroy (67), American Collin Morikawa (63), Colombian Sebastian Munoz (67), Englishman Paul Casey (68) and Chile's Mito Pereira (68) all finished at 15 under alongside Pan to force unprecedented extra holes requiring two groups for seven players from seven different countries.

Smith made a bogey on the last hole in a second successive round of 66 to miss the playoff at the Kasumigaseki Country Club.

The Australian No.1 not only rued his last-hole bogey on Sunday, when he was unable to get up and down after finding a fairway bunker off the tee and missing the green with his approach, but also some wretched luck in round two.

Smith's double bogey at the same hole on Friday, after his ball ricocheted sideways off a grandstand and into the water, ultimately cost him the bronze.

A par then and the only playoff would have been between Smith and Sabbatini to decide the silver and bronze medallists.

"I did my best but it just wasn't good enough. It wasn't to be," Smith said.

But he went mighty close.

A brilliant burst of five birdies in seven holes vaulted the 27-year-old into a tie for fourth mid-round.

After dropping a shot on the 12th, Smith needed something special.

He delivered by driving the green on the par-4 17th for another birdie to charge into a share of third place.

Alas, Australia's 2020 Masters runner-up faltered on the last to walk off utterly deflated.

"It's definitely a different week in that there's only three places you want to be," Smith said.

"In a regulation PGA Tour event, If I'd walked off the 18th green in fifth or sixth or whatever position I finish in, I'd genuinely be pretty happy.

"It's just a bit of a different feeling and obviously I'm a bit bummed to end it like that."

Starting the day seven shots adrift of Schauffele, Sabbatini reeled off an eagle and 10 birdies to snatch the clubhouse lead at 17 under.

In complete control for much of the day, Schauffele looked to have unravelled with two wild tee shots on the par-5 14th.

After fearing he'd lost his first drive into the trees left, Schauffele's provisional also struck deep trouble.

But, in a huge break, officials found his initial ball, the world No.5 took an unplayable and made a brilliant up and down from the fairway to make bogey when a triple-bogey looked very much on the cards.

The single dropped shot left the American in a tie with Sabbatini, but a birdie on the 17th hole then a clutch par saver at the last sealed the gold for Schauffele.

"I really wanted to win for my dad," said the world No.5 and highest-ranked player without a major.

"I am sure he is crying somewhere right now. I kind of wanted this one more than any other."

Australian Associated Press