Un Hinged produced a telling turn of foot on the run-in to claim the two-mile conditions hurdle at Navan.
8/11 Prince Of Fire had looked set for victory after hitting the front at the second last.
Ruby Walsh produced a late charge from Un Hinged, however, to grab that rival close home for a half-a-length victory.
"The Pierse had been the plan for ages but with 30 runners, and him being a hold up horse, he was always going to be too far off them," said trainer John Coleman.
"He pulled out fresh after that and with the small field here we decided to let him take his chance. Ruby said he hated the ground."
