Faugheen demonstrated his enduring class with a thrilling victory in the Flogas Novice Chase at Leopardstown.
The 12-year-old joint favourite, ridden by Paul Townend, held off the challenge of Easy Game by just half a length to the delight of the Dublin crowd.
It was a 17th win out of 25 races, and an impressive 11th Grade One success for the horse nicknamed 'The Machine'.
"I was absolutely delighted," said trainer Willie Mullins.
"I've had lots of winners before, but this was special, I think.
"They said it was special when he won down in Limerick at Christmas, but I wasn't there.
"This is fantastic here - it's probably one of the most special winners I've ever had."
Faugheen only moved up to steeplechases last year, and after wins at Punchestown and Limerick this was expected to be the big test.
The 2015 Champion Hurdle winner showed that champion's instinct by defeating horses less than half his age.
But while other horses are retired, Mullins knows he has a special talent at his stables.
"People want to retire horses at 10, 11 or 12, but to me they have plenty of life in them if they haven't used up the mileage as younger horses," he said.
"They can go much longer than people think and he's the living proof of it."
Kennedy breaks leg after Irish Gold Cup win
On day two of the Dublin Racing Festival, feature race the Irish Gold Cup was won by Jack Kennedy aboard Delta Work.
The Pat Kelly-trained horse finished ahead of favourite Kemboy, with Presenting Percy third.
All three had a chance coming off the last fence, but Delta Work crossed the line one and a half lengths clear.
It completed an impressive double after winning the Savills Chase at the same track at Christmas.
But joy turned to heartache for Kennedy just half an hour later.
The 20-year-old, who claimed the big race for trainer Gordon Elliott, looks likely to miss next month's Cheltenham Festival.
He fractured his right femur in the subsequent race when unseated from his mount, Dallas Des Pictons, at the first fence.
Kennedy had only recently returned to action after a collarbone injury and is expected to have surgery on his leg on Monday.
Delta Work is now joint 4-1 favourite with some bookmakers for next month's Cheltenham Gold Cup, alongside last year's winner Al Boum Photo.
BBC Horse Racing correspondent Cornelius Lysaght
Faugheen is simply a jump racing legend, the winner of a string of Grade One races, but also, crucially, a horse that's more than once bounced back from being written off.
This win represents just such an occasion, and at the grand old age of 12, equine 'bus pass' territory and far older than 99.99% of novices.
The crowds loved it, squeezing eight to ten deep around the winners' circle to welcome him. It was reminiscent of the joyous scenes of celebration that accompanied 1990s star Danoli when he raced at Leopardstown, and a rare pleasure to witness.