Chancol denied long-time leader Un Beau Roman to take a dramatic Madigans Bars Craddockstown Novice Chase at Punchestown.
Un Beau Roman jumped well in front and soon held a clear advantage, but his stablemate Alelchi Inois, the 11-8 favourite to defend his unbeaten record over fences, made a bad error seven out and though Ruby Walsh did remarkably well to stay in the saddle, he had to be pulled up.
At the business end only Chancol (3-1) and Paul Carberry had a real chance of catching Mikey Fogarty's mount approaching three out, but he too looked to tire coming to the second-last, only to dig deep from the final fence to get up in the last 50 yards.
Winning trainer Noel Meade said: "I think he'll improve because he's so big. He's still light and when he fills out he could be anything. Because of that I don't want to run him too often. Fences are a big help to him, as he jumps so well.
"Mags O'Toole spotted him at the sales and said I had to buy him. I'd never heard of his sire, but she said 'don't mind that, just look at the horse' and she was right. He's very clean winded and doesn't take a lot (of getting ready)."
RaceBets gave Chancol a 20-1 quote for the Arkle at Cheltenham.
Liz Doyle's Pairofbrowneyes (7-1) returned from a lay-off since early March with a gutsy victory in the Go Racing In Kildare 2015 Membership Handicap Hurdle, leading on the run to the last under Mikey Fogarty and holding Pivot Bridge by a length and a quarter.
The trainer said: "I thought he'd win and I felt he was my best chance of the weekend. He was on the bridle the last day, but just didn't get home. He just wanted to be dropped back in trip.
"He was spot on today and off a mark of 114 I thought he had to win. He'll go for something nice after Christmas. It just took the trainer a while to work out his trip."
Davy Russell travelled best on Lite Duties in the closing stages of the Flynn & Lynch Life And Pensions Supporting Longford GAA Handicap Hurdle and when he popped the question, Charles Byrnes' charge (11-4) went four and a half lengths clear.
Byrnes said: "A horse fell in front of him at the second-last the last day at Cork, and only for that he would have been closer. He'll tip away in those handicaps."