Last Instalment returned to his very best when making most of the running in the Hennessy Gold Cup Chase at Leopardstown.
The nine-year-old had been off since February 2012 when he came back last month and caused a minor surprise in this three-mile Grade One.
The 8-1 chance, trained by Philip Fenton, powered home in the hands of Brian O'Connell.
Tidal Bay finished with a flourish to claim second place.
O'Connell said: "He was exceptional. It wasn't the plan to make the running, but it's worked out in a slow-run race."
Owners Gigginstown House Stud had three in the race, with Roi Du Mee taking an early lead before Last Instalment jumped ahead at the second fence.
O'Connell let him bowl along in front and he took a few lengths out of the field on the turn for home.
First Lieutenant, in the same colours and the choice of retained jockey Bryan Cooper, tried to make a bid as the 7-4 favourite, but Last Instalment had other ideas.
He was not for stopping and galloped on strongly to score by eight and a half lengths from Tidal Bay (5-2), with First Lieutenant third and Texas Jack fourth.
O'Connell said: "We went very slow and I found myself in front after the second, so rather than pulling and dragging him I thought it better to let him lob along in front rather than being in behind.
"I kicked off the bend and he winged the second-last. He's a proper one.
"All credit to Philip Fenton. He's looked after him and has taken his time with him. He hasn't rushed so it's fair play to the owners.
"This is special. You have to be thinking of the Gold Cup now. I'm delighted to have my day."