Monbeg Notorious followed up his Thyestes Chase success with a narrow call over stablemate Mossback in the Ten Up Novice Chase at Navan.
The Gordon Elliott-trained pair had the four-runner affair between them in the closing stages and it was Monbeg Notorious who led home a one-two for owners Gigginstown House Stud.
Moulin A Vent set out to make all but was a sitting duck for the Elliott duo, who pounced with two fences left.
Monbeg Notorious (5-4 favourite) led before the last, but in the end was all out under Jack Kennedy to prevail by half a length. Moulin A Vent was left 19 lengths away in third.
Monbeg Notorious was cut to 6-1 from 10-1 for the four-mile National Hunt Chase at Cheltenham with Paddy Power.
Elliott said: "They are two grand, honest, galloping horses - big staying chasers. They are both in the BoyleSports Irish Grand National, and we'll see what happens. They wouldn't want firm ground."
It was a Grade Two one-two double for Elliott after Diamond Cauchois' win over Lieutenant Colonel in the Boyne Hurdle.