The 11-year-old (33-1) ridden by Mark Walsh passed fellow long shot Dasher Drasher (40-1) and favourite Teahupo'o (4-1) on a burst up the final hill to take the 182,878 pound ($221,538) prize in the three-mile test of stamina.
"He loves Cheltenham. He needs a bit of encouragement, but once he got to the hill, he stuck his head down and got it," Walsh told the BBC.
Dasher Drasher appeared to take second by a nose, but after a stewards' review, was dropped to third, and favourite Teahupo'o bumped to second.
Walsh said he had been in a rush to return after fracturing a vertebrae in his neck at the Dublin Racing Festival, and gave credit to his medical staff after the win.
"They patched me back together to make this week and I'm delighted," Walsh said.
Dashel Drasher was dropped to third, a move that cost 38,000 pounds in prize money, because his movement at the last hurdle forced Teahupo'o jockey Davy Russell off his line.
"We felt that ground that was taken off his intended line at a crucial stage of the race made the difference," chief steward Shaun Parker told ITV Racing. "We felt after what happened at the final hurdle, the fair result was to amend the result."
