Adam Scott's US PGA Tour season is over after a spectacular collapse at the second FexExCup play-off event.
Scott dropped four shots in his last four holes during a final-round five-over-par 75 at Olympia Fields to miss the cut for this week's lucrative 30-man Tour Championship in Atlanta in dramatic fashion.
After starting the round in third spot and well in contention for the title, and only needing a top-17 finish to make Atlanta, Scott imploded down the stretch.
He took a disastrous double-bogey seven at the par-5 15th hole, then leaked further shots on 16 and 18 to wind up equal 25th at six over for the tournament, 10 strokes behind victorious Spaniard Jon Rahm.
In a pulsating climax featuring the world's top two players, Rahm (64) denied American Dustin Johnson (67) in a playoff after draining a moster 66-foot putt on the first extra hole.
World No.1 Johnson had dropped his own long-range bomb on the 72nd hole to force the playoff.
While Scott's season is over, fellow Australian Cameron Smith clinched his spot at the Tour Championship with a joint-20th finish after closing with a 69 for a five-over 72-hole total.
He will be joined in the elite, no-cut field by Marc Leishman, despite the Victorian's diabolical display at Olympia Fields.
Leishman was dead-last of the 69 starters at 30-over par after a final-round 73, his best effort of a horror week.
Already well out of contention but guaranteed a Tour Championship start, Leishman played by himself on Sunday and admitted to lacking motivation.
"Just struggling with energy and that sort of thing on the course, not playing great either," he said.
"Yeah, I don't know what it is. Just haven't been much fun on the golf course, either.
"It's a tough game. We all know that.
"This is why you celebrate your wins so hard because you're going to have times like this.
"You hope you don't but you've got to take the good with the bad.
"I'm going through a rough patch at the minute but hoping to turn that around next week for sure."
Leishman will tee off in 25th position in Atlanta on Friday, at one under and nine shots behind Johnson.
"If I have a blinder next week, anything can happen," Leishman said, refusing to throw in the towel.
Smith will start at even with the card, 10 stroke adrift of Johnson and needing a miracle to claim the $US15 million ($A20m) winner's purse.
Along with Scott, fellow former world No.1 Jason Day's 2019-20 wrap-around season is also over after finishing 64th, at 14 over, in Chicago.
But Day will at least carry some momentum into the year's final two majors, the US Open in September and Masters in November, after closing with a nice two-under 68.