Drop Out Joe gave conditional jockey Graham Watters the biggest success of his short career when storming home in the John Smith's Summer Cup at Uttoxeter.
Only Ballynagour stood between the 20-1 chance and victory in the valuable Listed handicap chase over three and a quarter miles at the last of the 20 fences.
Charlie Longsdon's charge jumped it well and saw off the David Pipe-trained Ballynagour to score by two lengths in the hands of the 5lb-claiming Watters.
Pacha Du Polder was five lengths further away in third place, with Gas Line Boy fourth. The popular Menorah came next after a creditable effort off top weight.
There was drama at the very first fence where the 11-2 favourite Al Co blundered and unseated Jamie Moore.
He had replaced Sean Bowen after he had been stood down following a fall from Beneficial Joe in the opening hurdle race.
Al Co's Peter Bowen-trained stablemate, Tony Star, made the running until the fourth-last fence where the winner Drop Out Joe took over.
Longsdon told At The Races: "We gave him the entry, but wondered if he was a summer horse - however, the ground these days is so good, Charlie Moore and his team do a great job here.
"We have him four weeks off after the Whitbread (Bet365 Gold Cup) where he clearly wasn't at his best, he's come back and done it.
"I never thought he'd be winning races off 144, but he's done it well. He won 50 grand plus last season, and now he's just won a 43 grand pot. Fantastic.
"There were some seriously good horses today, when you see horses like Menorah hanging around for the summer, there's no such thing as weak summer racing now.
"There's no hiding place, you just need a good horse and if you can pick up one like we've just done it pays off."