The 14-1 shot, ridden by Andrew Tinkler, beat Same Difference in a charge to the line up the straight after the pair had pulled clear of the field.
Hot favourite Away We Go - priced at 9-2 before the start - looked well placed until a mistake at the penultimate fence saw him lose ground, and he ended up in third place.
The winner's trainer admitted that the horse wasn't even supposed to be in the race, but took part after bad weather ruled him out of the Scottish Grand National in Ayr last week.
"He's not big enough to jump the fences when it's soft so he's had a light campaign," he said, adding that the diminutive horse has little prospect of ever being competitive at the Grand National at Aintree.
"I'd imagine he'll go for good staying chases next year, but he's so small that the National fences would seem very big for him. It's something we'll have to think about."
Over in Ireland on the final day of the Punchestown Festival, Glens Melody won the Irish Thoroughbred Breeders Association Fillies' Scheme EBF Mares Hurdle, bringing a winner for Paul Townend after a disappointing week.
The 7-2 shot picked up the pace from the second-to-last fence and pulled away from Shadow Elie to win in impressive style.
Meanwwhile, AP McCoy was crowned champion jockey for the 18th consecutive year despite being ruled out of racing after a fall earlier in the week.