Reve De Sivola made all of the running to claim back-to-back renewals of the Wessex Youth Trust Long Walk Hurdle at Ascot.
Trained by Nick Williams and ridden by Richard Johnson, the eight-year-old's stamina came to the fore in the exacting conditions at the Berkshire circuit as he gamely held off Salubrious by 10 lengths.
At Fishers Cross, the 8-11 favourite, ditched jockey Tony McCoy at the final flight.
Johnson said: "He's a very honest horse - he's a very good horse.
"He's a very, very good hurdler and we know soft ground suits him very well."
At Fishers Cross had jumped sketchily early on, but improved along the second circuit as he strived to atone for an awful mistake at Newbury on his seasonal bow.
Rebecca Curtis' inmate made another howler here as he catapulted McCoy out of the saddle when in second place.
Connections of Salubrious might also feel a little hard done by as the six-year-old made a costly gaffe two out when seemingly still full of running.
Reve De Sivola (9-4) was hardly flawless in the jumping department, but he adores a scrap in the mud and, crucially, kept his cool while his pursuers faltered.