Fact To File pipped Spillane's Tower to win the John Durkan Memorial Punchestown Chase in the second day of the Winter Festival.
The race marked the return of dual Gold Cup winner Galopin Des Champs and a renewal of the Paul Townend ridden horse's rivalry with Fastorslow.
The established pair looked strong off the mark and, as the race reached the home turn, Galopin Des Champs led the star-studded field.
But between the final fences, last season's form novices Fact To File and Spillane’s Tower closed the gap.
After both showed their pedigree with a pair of wins at the highest level as a novices last term, the JP McManus owned duo finished strongly and went head-to-head over the final half-furlong.
Fact To File, under Mark Walsh, edged to victory to give trainer Willie Mullins a 10th win in the race.
Galopin Des Champs was two and a quarter lengths back in third with Fastorslow in fourth.
"It was a terrific race – it was probably the best John Durkan I’ve seen," Mullins told RTE.
"Fact To File is a proper racehorse, it’s going to be a hell of a season.
"I was really taken by Fact To File and what he did from the last to the winning post. I thought he was beaten by Spillane's Tower, but Fact To File put his head down."