Sean Flanagan set out to make this near two-and-a-half-mile trip a test of stamina as the Noel Meade-trained grey was last seen winning the Champion Novice Chase over an extended three miles at Punchestown in April.
It proved a sound tactic as Disko (5-4 favourite) maintained a strong gallop. He was shadowed throughout by Ballyoisin, but always had his measure and pulled out extra on the run-in to score by half a length.
Meade said: "He's a gorgeous horse to have and we're delighted that he won and he won well.
"It was a tough task because he was giving away weight to everything.
"He did get a little bit tired but he's entitled to. The second horse was well in at the weights on his rating and he's a fair horse as well. We're thrilled with him.
"I don't know if maybe the John Durkan might be considered with him. It possibly would and he'll certainly be entered in it anyway.
"I honestly think three miles is his best trip. I've always thought stamina is more his forte. He goes a good gallop and keep going."
It was a good day for owners Gigginstown House Stud as they also won the feature JNwine.com Champion Chase with Outlander and the concluding bumper with Rapid Escape (11-10 favourite).
That duo are trained by Gordon Elliott, who had a third winner courtesy of Poormans Hill (5-4 favourite).
The six-year-old completed a four-timer in the Rainbow Communications Handicap Chase, while his rider Jack Kennedy was also aboard Outlander.
However, it was not all plain sailing for Elliott and Kennedy as they received the wrath of the stewards over the running and riding of Suitor, who finished third behind Ten Ten, beaten a total of 18 and a half lengths, in the Tayto Group Maiden Hurdle.
Kennedy was suspended for five days, Elliott fined €2,000 and Suitor banned for running for 42 days.
Espoir D'Allen (2-5 favourite) looked a decent prospect when comfortably landing the odds in the Value Cabs 3-Y-O Hurdle at Down Royal.
Trainer Gavin Cromwell said: "That was good. I suppose the Grade Three in Fairyhouse is the obvious place to go as it's a month away."