Philson Run shrugged off his lack of experience to grind out a famous victory in the John Smith's Midlands Grand National at Uttoxeter.
Nick Williams' nine-year-old, a 14-1 shot, was always going well under Paul Carberry in the stamina-sapping race over four miles and a furlong.
After giving Philson Run a patient ride in the early stages, Carberry joined the leaders leaving the last bend.
And he was left out in front when D'Argent, the 5-1 favourite, blundered and unseated Robert Thornton at the third last.
Philson Run eventually finished a length ahead of Toulouse-Lautrec (7-1), with Howdydoody (8-1) another seven back in third and L'Aventure (12-1) in fourth.
Amazingly, Carberry nearly missed the ride after weighing out with only a minute and a half to spare.
"Mattie Batchelor was on standby," said Williams.
"Ruby Walsh said he'd spoken to Paul and he said he was on his way. I was not confident he'd get here - more hopeful.
"Dave Dennis would have ridden him but he couldn't do the weight."
The trainer is hoping that if his charge stays sound he could develop into a Grand National contender next season.
"We had him as well as we possibly could given his legs are a bit fragile and when we were being caught on the run-in I was a bit worried we hadn't done enough," Williams said.
"When D'Argent went three out that obviously helped.
"He's in the Scottish National but it would have to be on the soft side. He wouldn't go if it was fast ground.
"If he keeps sound we'll look at the Becher Chase and Grand National next season.
"He wasn't high enough in the weights to get in the National this year but he will be now."
Explaining his late arrival Carberry calmly said: "There was no rush. I just had the one ride so I just came in time for it."