Benefficient produced a gutsy performance to deny hot favourite Dynaste in the Jewson Novices' Chase, the opening event on the third day of the Cheltenham Festival.
Tony Martin's charge was allowed to go off a 20-1 shot in the hands of Bryan Cooper but he made a mockery of his odds as he accounted for Dynaste by three and a quarter lengths in a thrilling finish.
Cooper had been positive from the off aboard Benefficient, disputing the early lead with Molotof behind as Dynaste began to make his move six fences from home.
Tom Scudamore let the favourite assume the lead at the top of the hill and Benefficient looked set for third at best as David Pipe's Dynaste pushed on in company with Captain Conan.
Ruby Walsh was also making stealthy progress aboard Marito in third but he crashed out at the penultimate fence as Captain Conan's challenge began to falter.
Cooper had kept his cool when headed, switching Benefficient back to the inside before jumping to the front at the last.
Dynaste did his best to keep on terms but Benefficient demonstrated plenty of stamina as he powered up the hill to claim Grade Two glory.
Changing Times, a 100-1 shot, finished fast for third place, a further length adrift.
Cooper said: "It's unbelievable, it's what you dream of as a young boy.
"Tony said to me that if he gets headed turning in, to just sit on him and let him fiddle away.
"Some of the others might have had more speed than him but they couldn't get away from me.
"He winged the last and galloped all the way to the line."
Martin said: "This is what you get up every morning for, to come here with a live chance.
"I thought if everything went well he couldn't be out of the first three but we were very much afraid of Dynaste.
"We knew he'd get two and a half miles, he got the run of the race and jumped excellent and the jockey was excellent.
"As far as I'm concerned Ruby Walsh, Barry Geraghty, Paul Carberry and Tony McCoy are out on their own but they are the old guard, this boy is on the way up and he'll be there when they have long gone.
"He's a good moving horse and the better ground helped him.
"Today was the plan."
Paddy Power offer 33-1 about the chances of Benefficient in next year's Betfred Cheltenham Gold Cup while Will Hill go 25-1.
Scudamore said: "He's run a great race and he's the best of the English horses.
"He jumped fantastically and was beaten by a better horse on the day.
"It seems that the Irish staying novices are better this year."
A terse Pipe said of Dynaste: "Just not good enough. He might go to Aintree but I'm happy we picked the right race."
Further disappointment came for Scudamore in the shape of a two-day whip ban (March 28 and 30).
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