The six-year-old is a son of former Smart star Captain Gerrard and a half-brother to Tangerine Trees, who won the Prix de l'Abbaye for the same connections on this weekend six years ago.
Alpha Delphini opened his account on the Westwood a couple of years ago and produced what was comfortably a career-best performance at the time when landing the Beverley Bullet last summer.
He has unsurprisingly found life a little tougher since, but was far from disgraced in finishing seventh when defending his Bullet crown late last month and he was the 5-4 favourite having had his sights lowered in the Eddie And Violet Smith Conditions Stakes.
Alpha Delphini tracked the pacesetting Elysian Flyer before hitting the front inside the last of five furlongs under Graham Lee and he had enough in the tank to score by a neck from Line Of Reason.
Smart, celebrating his 61st birthday, said: "I'm really, really pleased with that as he just needed to get his confidence back.
"We might have a look at the Rous Stakes (Ascot, October 7) but next year this horse will get six (furlongs).
"If you looked at his Bullet run, he ran well as he didn't have a chance with that draw.
"He loves it at Beverley and it's nice for all of his owners, who are local."
There was a dramatic start to proceedings in the opening Beverley Annual Badgeholders Novice Auction Stakes.
Richard Fahey's Requinto Dawn, the 15-8 favourite under 7lb claimer Sebastian Woods, passed the post a nose in front of Julie Camacho's 3-1 shot Weeton, ridden by Joe Doyle.
But the stewards reversed the placings after Requinto Dawn was deemed to have interfered with Weeton on the run to the line.
Camacho said: "I've only seen it live, but I thought they were two tired horses in what was pretty testing ground.
"I'm delighted for his owner Mr Armstrong and his family as the horse deserved his win.
"He is going to the sales as the Armstrongs have plenty of young horses coming on."
Fahey admitted to being taken aback by the decision.
"Maybe the stewards have different camera angles to what I've seen, but I was very, very surprised - shocked, even," said the Musley Bank-based handler.
"I've spoken to the kid (Woods) and he was very disappointed."
When asked about the possibility of an appeal, Fahey said: "I've only seen the race once, but I'm sure my owners would want me to do my best for them."
There was no denying Fahey in the Pony Racing Here On 1 October ebfstallions.com Novice Stakes, with his 7-2 chance Buckstopper Kit knuckling down well for Paul Hanagan to see off Big Kitten by a neck.
"He's a very tough horse but he's a very lazy horse, which he's why we've put the blinkers on him - not because he's ungenuine or anything like that," said the trainer.
"He doesn't know he's a racehorse yet and he could end up being a nice horse."
Intense Style (15-2) recorded his first victory in over a year in the Colin McGurran At Beverley Racecourse Handicap.
Les Eyre's charge got the better of Kirkham by a neck in the hands of apprentice Faye McManoman.
Eyre said: "This horse will just not go for a fella.
"She (McManoman) came down and rode him on Friday and he took off with her, so I just thought, 'that'll do for me'."
The formidable combination of trainer David O'Meara and jockey Danny Tudhope landed the Season Finale Handicap with 15-2 shot Pioneering.
Kohinur (4-9 favourite) looked sure to reward odds-on backers when pushing on in the Beverley Interactive Maiden Fillies' Stakes, but she was mowed down late by Iain Jardine's 3-1 shot River Icon, with 5lb claimer Callum Rodriguez doing the steering.