Peter Casey's Flemenstar routed the opposition in the Powers Gold Cup at Fairyhouse.
The Irish Arkle winner jumped superbly throughout in the hands of Andrew Lynch and must now be rated a serious prospect for next year's Cheltenham Gold Cup.
Rathlin put the pace to the race under Davy Russell with Flemenstar sat three lengths behind as False Economy and Call The Police tracked the 11-10 favourite.
Approaching the third last Lynch asked Flemenstar to move upsides Rathlin and a good leap took him clear.
The seven-year-old, racing on the fastest ground he has tackled this season, really quickened and sprinted to an 11-length win over some top-class rivals.
Casey said: "I can't believe it. I can't believe he's that good, I'm delighted with him.
"I want to thank the sponsors and also the people who look after the track here, they've done a great job.
"They said he wanted soft ground but we thought it made no difference, he went on good ground here last year over hurdles.
"My son has been over to keep an eye on the ground two or three times this week and we were happy.
"He's won so much now and is so valuable you don't want anything to happen.
"He's been nearly sold two or three times but I'm delighted he wasn't.
"My son said to me he destroyed them and he did.
"He won't go to Punchestown, we entered him last week in case anything happened here."
Lynch added: "He has plenty of gas and does everything so easy. He has got gears but probably wouldn't want the ground any quicker."
Flemenstar's owner Stephen Curran said: "We are lucky to have him. It's great to have a nice horse."
Casey confirmed that Cheltenham will be on his agenda next March having skipped the meeting this season.
War Of Attrition in 2006 was the last Irish-trained horse to win the blue riband event.