Don Poli dug deep for Bryan Cooper to claim top honours in the Topaz Novice Chase at Leopardstown.
Winner of the Martin Pipe Conditional Jockeys' Hurdle at last season's Cheltenham Festival, the Gigginstown-owned five-year-old made a successful start to his chasing career at Gowran Park and was the 9-4 favourite stepped up to Grade One level over fences.
Willie Mullins' charge moved to the front in the straight after having jumped soundly from the outset, but he was tracked by the Noel Meade-trained Apache Stronghold.
Apache Stronghold looked set to prevail after hitting the front after the final fence, but it turned into a real war of attrition on the run to the line and it was Don Poli who saw out the punishing three miles best to prevail.
Mullins said: "The penny is dropping all the time. He's a lovely horse with lots of ability.
"I had nominated the four-mile chase (at Cheltenham) as his long-term objective but Mr O'Leary (Michael, owner) has so many horses, he might have other horses for the RSA and maybe this fellow is an RSA horse.
"I don't know, but certainly four miles will be no problem to him.
"I've been saying all week it was probably the best Topaz Chase that's ever been run here.
"He is improving all the time and he could be anything - he could be a Gold Cup horse."