So Young got the better of his stablemate Zaidpour to run out an impressive winner of the Red Mills Trial Hurdle at Gowran Park.
Often used as a Champion Hurdle trial by the likes of Hardy Eustace, So Young only holds an entry in the World Hurdle at Cheltenham, but showed surprising speed under David Casey.
Arnaud was flanked by the Willie Mullins pair over the second-last and while Zaidpour, the 4-6 favourite, had the advantage of the rail, it was So Young (11-4) who sprinted clear to win by six lengths.
Mullins said: "That's his first Graded win, but he's always promised to win one. He made a bad mistake at the last when he would have gone close in the Neptune at Cheltenham and we've never been able to get him to do that again.
"We changed a few things at home with him and it looks like it might have paid off. We keep thinking he's a two-and-a-half-mile horse, but we brought him back to two miles today.
"I thought Zaidpour would have won, but Paul (Townend) said he was never really travelling after he made a bad mistake.
"They'll both be entered at Cheltenham, but there are nice prizes at home for them both and it may be best to keep them at home.
"They'd be going there with a little chance, but both have been well beaten there even though they've run their races before."
30 September 2014Power primed to storm Abbaye
Creepy excels on chasing bow
Al Kazeem given Arc go-ahead
Buick makes Ivanhowe Arc link
Power heads Abbaye market
Martin keen on Clonard
Cirrus heads Longchamp billing
Elite aim for Irving
Ribbons run hinges on Paris ground
No fitness worries for Lemaire
Quick on course for Ces date
Beaux plans undecided
Foret-bound Byron enjoys workout
Perfect fencing start for Minstrel
Ted takes Roscommon honours
Rain fillip for Treve Arc challenge
Speed not an issue to River camp
Signal on course to Wow in Paris
Ivawood heads Millions field
Top fillies star in Chariot race
Point primed for Abbaye assignment
29 September 2014Logic ruled out for the season
Ansgar in Foret frame
Kalann team consider Champions bid
Peslier and Mosse hunt Arc mounts
O'Brien trio set for Longchamp
High hopes for Elliott team
Berry takes the rails route
River cruises to Beresford glory
Qualify swoops for O'Brien team
Minstrel ready for chasing bow
Tiggy Abbaye run not set in stone
Angel camp ponder Darley raid
Pineau ripe for new season
Mubtaghaa suited by joy of six
Fiesolana fired up for Foret
28 September 2014Keighley holds Court for Cheltenham
Mart makes Newland's day
Spin does the trick at Ripon
Angel heaven-sent for Tregoning
Tiggy takes Cheveley gold
Lodge proves a stroll in Park
Rosalie blossoms for hat-trick
Naylor seeking Paris prize
Integral on course for Chariot
Dettori anticipating 'vintage' Arc
27 September 2014Fox on prowl for Rasen riches
Educate out to teach lesson
Euro raiders land in Australia
Tributes pour in for Toby Balding
Bans made after McCoy incident
Ground key to Muthmir run
Leather in Ascot picture
Custom proves cut above
Lucida rocks in Rockfel
Etaab delivers in Haggas double
Cosgrave cleared to continue riding
Cumani sees positives in Velox