The youngster, enjoying a sixth success, is a student at Clongowes Wood College in Co Kildare and this was the biggest win of a fledgling career.
Diego Garcia, 5-2 to 7-4, is trained by his father, Willie, who also saddled the second, Navajo Chieftan.
“I am delighted Patrick has won this so early, it took me 20 years to do it”, said Mullins senior. That was Future Hero in 1992.
On hand to watch was Patrick's legendary grandfather, Paddy Mullins, the man who trained Dawn Run to complete the famous Gold Cup-Champion Hurdle double at Cheltenham.
Navajo Chieftan, on the pace from the start, went on for Katie Walsh with well over five furlongs to run.
He was pursued to the straight by Pearly Jack, with Diego Garcia cruising in third spot. Navajo Chieftan kicked hard approaching the furlong pole, but the winner soon swept past and was a handy length and three parts to the good at the line.
“I trained the winner once before”, commented Mullins. “It was Native Darrig ('97) and Ruby Walsh rode it.
“Galway will probably come a bit quick, but he loves the place and may go there. He will definitely be heading to Listowel.”
Mullins landed a double when Bothar Na, partnered by Ruby Walsh, took the Gold Medal Handicap Chase in hugely fortunate circumstances.
Waltons Mountain, trained by his brother, Tony, had the race in safe keeping, about three lengths clear, when crashing out at the final fence.
Bothat Na was still only fourth at the obstacle, but stayed on best on the flat to beat Monterey Bay and Oh Be The Hokey.
“I would have won anyway”, said Walsh, utterly tongue-in-cheek. Willie immediately rang Tony to say “hard luck” and smiled: “His reaction was unprintable.”
The Kerry National at Listowel will be next for Bothar Na.
The contest won by Xinji at Gowran Park is looking an increasingly hot race. Already the fifth and sixth respectively, Great Sphinx and So Amazing, have won and yesterday it was the turn of Star Inside, who took fourth at Gowran.
He landed the Irish Stallion Farms' EBF Median Auction Maiden in smooth style, after Declan McDonogh had given him a very confident drive.
McDonogh was in no hurry, but there was only going to be one result once he asked Star Inside to quicken by Shabahar inside the furlong pole.
It was the 64th winner of the season for McDonogh and he now leads Johnny Murtagh and Pat Smullen by five.
Esteban was a desperately unlucky loser of the Grand Hotel Handicap Chase. Joey Elliott took him to the front before three out and he was clear when falling at the next.
Ichi Beau was left in the lead, but Paul Carberry soon swooped as Mango Catcher came from the clouds to ease past on the run in.
“He's been a bit unlucky”, said trainer, Paul Nolan, of Mango Catcher. “Esteban was very unlucky today and thankfully we were there to pick up the pieces.”
Pat Flynn continued his terrific run when Baby Blue Eyes easily won the DNG W.H Giles Auctioneers' Handicap.
Given a copybook drive by Danny Grant, Baby Blue Eyes mastered front-running Dapple Dawn, successful here on Wednesday, at the furlong pole.
The daughter of Cadeaux Genereux is in at Down Royal today and Flynn said: “one step at the time, but if she eats up she is likely to travel.”
Frances Crowley's Haroni stamped himself the best juvenile seen so far this season when outclassing his rivals in the Lee Strand three-year-old Hurdle.
Andrew McNamara made his move over the second last and Haroni quickly scampered away.
“I knew he had improved since the last day (Tramore) and this track suited him better”, reported Crowley. “He's a big horse and enjoys jumping.”
Cloyne, Co Cork handler James Motherway saddled Chairmanforlife to take the Bumper, the Bob Back gelding proving far too good for market principals, Old Parish and Off The Mark, in the closing stages.
“I knew if back to his Punchestown best (fourth to Glencove Marina) he'd win”, said Motherway. Chairmanforlife is owned by the six-member Friends Of Denis Syndicate from Cork city.
Joanna Morgan's Luckyvera, a close third earlier in the week behind Hit The Target, made no mistake in the Timmy Houlihan Memorial Handicap, powering through late for Kevin Manning to cut down Merlins Profit.