UN Atout was cut to 16-1 for the Supreme Novices' Hurdle by Paddy Power after an effortless debut over timber in the Kells Maiden Hurdle at Navan.
A wide margin winner of his only bumper, he runs in the Gigginstown House Stud colours and Davy Russell set out to be positive on the four-year-old.
Useful rivals Some Article and Fickle Fortune closed up but Un Atout (1-2 favourite) kicked clear of the latter to win by four and three-quarter lengths.
"We knew he would probably have to make the running but he was brave in front to go and make it first time over hurdles," said Mullins
"He jumped like a chaser early on but his jumping flattened out as he sped up.
"He's probably more of a stayer and he's a chaser for the future.
"We'll see how he comes out of this and we'll definitely have a look at Christmas. He'll be entered in all the top novice races."
Moscow Mannon, fourth in last season's Cheltenham Champion Bumper, made a stylish winning debut over jumps in the Irish Stallion Owners EBF Maiden Hurdle.
A triple bumper winner, Brian Hamilton's six-year-old made the transition to obstacles with the minimum of fuss as he set about the opposition.
Always in command, he was never seriously threatened as he swept to victory under Andrew Lynch by two and three-quarter lengths from the Mullins-trained The Paparrazi Kid.
Hamilton said: "I'm glad to get that out of the way and I can relax a bit now.
"I doubt he'll go to Leopardstown as he pulled muscles six or seven weeks ago which messed us up a bit. Leopardstown may come a bit quick.
"He'll probably go for the Slaney Hurdle (over two-and-a-half miles) at Naas (January 6). We'll step him up a bit and that's the idea at the minute.
"He should improve quite a bit from that run."
Russelll completed a double for the Gigginstown House Stud with a cosy win on the Mouse Morris-trained Rule The World in the Meath Novice Hurdle.
The 4-5 shot led two out and was not hard pushed to come home by four and a quarter lengths from Joncol, who gave his connections hope for a revival when staying on for second.
"He was workmanlike but Davy was happy with him which is the main thing," said Morris.
"He'd appreciate better ground but what can you do at the moment. There was an older/stronger horse in second there."
Roi Du Mee supplemented two wins over fences with a neat victory over the smaller obstacles in the Proudstown Handicap Hurdle.
The seven-year-old, completing a treble for owners the Gigginstown House Stud, was far too good for the opposition when giving 7lb claimer Jane Mangan an armchair ride.
Leading at the third-last flight, the 2-1 favourite overcame a mistake at the next and won as he liked by nine and a half lengths from Colbert Station.
"He's obviously better known as a chaser but it was a good pot here (?17,875 first prize) and we decided to have a go," said Elliott.
"He's been a great horse for us and it would be nice if we had a few more like him.
"He'll go for something like the Listed chase at Tramore on New Year's Day."
Oscars Well (8-11 favourite) ran out a comfortable victor in the Irish Stallion Farms EBF Novice Chase.
A Grade One winner over hurdles, he won on his chasing bow at Punchestown in October but was a faller there last time when a hot favourite.
He put that run behind him though with a confident round of jumping in the hands of Robbie Power, holding a healthy advantage at the top of the straight.
Cootamundra tried to make a race of it but Oscars Well was far too good, with his stablemate Jenari third.
Winning trainer Jessica Harrington tweeted: "Delighted to get Oscars Well back on track jumped great and Robert gave him a super ride."