John Daly slumped to a wretched 15-over-par 86 to tumble out of contention at the Justin Timberlake Shriners Hospitals for Children Open in Las Vegas.
The former Open and US PGA major winner is fighting to earn a tour card for 2013 and was ideally placed to move a giant stride towards that goal when he shot a 63 in his second round on Friday to climb to sixth place.
But as Jonas Blixt, Brendon de Jonge and Ryan Moore marched on untroubled at the top of the leaderboard, all reaching 19 under par to share the lead after three rounds, Daly endured one of those days of which he is capable.
He will start Sunday's final round in 72nd place, last of all those who made the cut, on five over par.
Saturday's score from the 46-year-old was, by nine strokes, the worst in the field, and the damage came early, Daly starting with a par but then making a mess of two chips to double-bogey the par-four second and following that with a quadruple-bogey eight at the third.
He dropped shots at each of the next two holes too, so any thoughts Daly had of staying in contention were already banished by the turn, which he reached with a birdie at the ninth, in nine-over-par 44.
A double bogey at the 10th, a triple at the 12th and another pair of dropped shots came and went, before Daly hooked a shot back with a two at the 17th and completed his round with a par.
Even by Daly's sporting standards, which slipped low during the darkest days of his career, when he struggled with alcoholism and gambling huge amounts on the nearby Strip, it was a bad day on the course.
Meanwhile Blixt, De Jonge and Moore relentlessly drove further under par on a course made for low-scoring.
Sweden's Blixt and Zimbabwean De Jonge both signed for five-under-par 66s, while Moore, who had an opening 61 but slipped back on Friday, returned to a share of the lead with a bogey-free 65.
The front-running trio were five strokes clear of the rest, with Moore's fellow Americans Jimmy Walker and Tim Herron tied for fourth place on 14 under.
Scotland's Russell Knox impressed with a 68 moving him to 12 under for a share of sixth place.
United States Ryder Cup captain Davis Love III began his week with two solid sub-par rounds to reach seven under but slipped two shots after a 73.
He remained safely under par though, as did all but two players: Hunter Hamrick, two over after a 77, and the misfiring Daly.
By taking 23 more shots to complete his third round than he did his second, Daly stands to only take away pocket money this week when a big cheque was in the offing.
The big bucks would have been useful, but he now stands to be 134th on the PGA Tour money list after Sunday's final round, with cards for next season going to the top 125. There is still ample time for Daly to climb the table, but he may have few chances like the one he blew Saturday.
Daly wrote off his performances as "just a rough day" when he could not string anything together.
"I can't remember a time when I had a stretch of so many bad holes," he said.
"I hit a couple of bad shots but didn't really hit that many bad shots. This course, everybody shoots it low, but there's times where nothing just goes right.
"I short-sided myself all day. If I missed a green, I had the most impossible chips. I couldn't make a four-footer today, and I had the lefts going, which usually if I miss the ball, it's right, so that confused me a little bit.
"It's almost like, when you get off to a start like that, your body just almost goes into shock, and every time I tried to hit a cut, I'd hit a pull, and every time I'd try to hit a draw, I'd flare it right.
"I asked Johnny the scorer when I got done if there was a chance I could get my amateur status back, and he said, no, it would take too long.
"It's just a rough day. Just a tough day, and the good shots that I hit, like on 17, I was able to chip in, but it was like that all day, if I hit a really good shot, it just turned out bad. Just one of those days."