Siegemaster put up a tremendous weight-carrying performance to land the showpiece Connolly's Red Mills Thyestes Chase at Gowran Park.
The Dessie Hughes-trained 10-year-old (16-1) was nursed into contention by Davy Russell, who had to pass the doctor after a crunching fall on Thursday, and came to tackle favourite Alpha Ridge in the final straight.
Russell conjured good leaps from the top-weight when it mattered and while The Midnight Club threw down a huge challenge, he had to settle for second-best as Siegemaster held on by three-quarters of a length, with the runner-up's stablemate Ballytrim third.
Hughes said: "It's great to finally win it - I'd never won it as a jockey or trainer before today.
"He was upsides with Whinstone Boy at the last when third in this last year and was a lot better off at the weights with him, so he had a chance. The older he gets the easier it is for him to carry these big weights.
"We'll probably look at the Irish National for him now and there might be something before then for him. He might go to Aintree next year."
Willie Mullins, trainer of the second and third, had better luck when Mourad (4-9 favourite) had no trouble in landing the odds in the Grade Two Galmoy Hurdle, and he could be a threat to Big Buck's in March.
Footy Facts and Powerstation set a generous gallop, but Paul Townend was virtually motionless as Mourad swept through the field to score by six lengths, with Moskova running on well from the rear to claim second.
"He seems to be improving and looks to be getting stronger with age. He did that on ground I don't think he particularly likes and he'll be better on better ground," said Mullins.
"Paul was very cool on him. It looks like we are on track for the World Hurdle."