Bobs Worth ground out victory in a compelling renewal of the Betfred Cheltenham Gold Cup under Barry Geraghty.
The 11/4 favourite, trained by Nicky Henderson, briefly lost his place on the run to the third-last fence, at which point Long Run, Sir Des Champs and Silviniaco Conti looked to have the race between them.
But Silviniaco Conti came down at that fence and gradually, as the climb up to the final two flights started to take its toll, Bobs Worth - despite being hampered by his rival's fall - steadily came back into contention.
Long Run (7/2), who had jumped better than ever in the early stages, produced another fine leap at two out as he tried to hold off his pursuers.
But he had no answer as stablemate Bobs Worth joined him on the run to the last fence and also forfeited second close home as Sir Des Champs (4/1) answered every call of substitute jockey Tony McCoy.
Credit must also go fourth-home The Giant Bolster, who might have finished even closer but for a bad blunder at the top of the hill.
At the line, Bobs Worth had seven lengths in hand over Sir Des Champs with a further two and three-quarters of a length back to 2011 winner Long Run.
"He just struggled in the soft ground most of the way," said winning rider Barry Geraghty.
"I thought I was beaten with six to jump but he started to run on down the hill and I knew at the third last that I had a chance of getting them.
"He coped with the ground but he would really appreciate better going. He's such a brave horse that I was only ever really asking for 80 per cent as I knew there was more there when I really needed it."
Willie Mullins, trainer of Sir Des Champs, said he felt that the rain-softened going had counted against his charge.
"He didn't appear to travel throughout - Tony was always niggling at him," said Mullins.
"I'd have preferred it if it hadn't rained. I'd like to bring him back for a better-ground Festival."
