Boston Bob (9-4 fav) stayed on best to land the Synergy Security Solutions Novice Hurdle at Leopardstown.
Willie Mullins' seven-year-old, owned by Graham Wylie, was giving weight to all of his rvials but showed an abundance of stamina in gruelling conditions to win by a couple of lengths under Ruby Walsh.
Dessie Hughes' Lyreen Legend (12-1) had tried to pinch the race under Bryan Cooper kicking for home but was overhauled at the final flight.
The previously unbeaten Make Your Mark (5-2), a stablemate of the winner, travelled powerfully but had no answers in the closing stages and finished well-held in third.
Mullins said: "There was a day we galloped a few at Thurles some time ago - horses we thought were top horses.
"One of the young lads in the yard was riding Boston Bob and he came through the other horses going easily and we thought that day we had a racehorse.
"I thought he had the size and scope to carry today's penalty but three out I wasn't so sure!
"Ruby said he hated the ground and his pedigree says he should go on better ground.
"He looks a big, strong chaser and we look forward to him going chasing next season. He could have gone chasing this season but we just decided to go through the motions over hurdles for now and it has taught him to race.
"I imagine he will go for the Neptune or the Albert Bartlett Novices' Hurdle at Cheltenham but we'll see what happens after the Deloitte Novice Hurdle on February 12 and where I go with my other horses.
"I imagine Ruby will ride him wherever he goes."
The winner was the second leg of a quick double for Mullins and Walsh following the earlier success of Hurricane Fly, and was cut by bookmakers for the Cheltenham Festival.
Sky Bet go 6-1 (from 12s) for the Neptune Investment Management Novices' Hurdle and the same price (from 9s) for the Albert Bartlett Novices' Hurdle.