Mourad proved far too strong for stablemate Mikael D'Haguenet in the Ladbrokes Boyne Hurdle at Navan on Sunday.
Ruby Walsh opted to ride the 4-11 favourite but the eight-year-old didn't hurdle fluently and he was in trouble as he tried to close down the all-the-way winner between the last two.
He never threatened to land a blow as Mourad, sent off at 3-1, powered home under Paul Townend to score by six lengths.
Mullins, winning his first Boyne Hurdle, said: "Mourad had been disappointing this year and I didn't think he was back to his form so we said we'd change tactics today and decided to make a lot more use of him.
"He seemed to enjoy it a lot better and it didn't do his travelling plans any harm (for the World Hurdle at Cheltenham).
"I'm disappointed with Mikael D'Haguenet. I'll have to think of plans now for him. On ratings there wasn't much between the two of them but the other fellow just found his form this year for the first time."
Paddy Power make Mourad a 14-1 chance for the World Hurdle at Cheltenham, while Stan James go 16-1 from 33-1.
Stan James' spokesman Joseph Burke said: "Willie Mullins now trains a quite amazing six of the first 10 in the betting for the World Hurdle and whilst Big Buck's remains the 1-2 favourite, Mourad was only four and a half lengths behind him last year so he must have an each-way again."
Sky Bet and Paddy Power were impressed by the performance and cut the winner to 14-1 from 33s for the Ladbrokes World Hurdle, while Stan James go 16s from 33s.
