The once-a-year fixture, which takes around 30 miles north of Dublin on the east coast, is the only race meeting run on a beach under the rules of racing in Ireland and Britain.
Having secured a winner in each of the last two years, Lambourn-based Osborne returned with a formidable team of eight runners across a six-race card which celebrated 150 years of racing at the County Meath venue.
Each of the Osborne runners carried the colours of Melbourne 10 Racing, of which Osborne is a fully-fledged member along with nine of his friends.
The syndicate were represented by 10 horses overall, after also leasing the Johnny Murtagh-trained Prosecution and Tom McCourt’s course winner My Good Brother for the day, with the latter just touched off in the last.
The heavily-backed Florencio set the ball rolling with victory in the O’Neills Sports 100 Years Centenary (Q.R.) Handicap under Lisa O’Neill.
Running off a mark of 75 – a stone lower than his all-weather rating of 89 – the 10-11 favourite eased to a one-and-three-quarter-length success.
When asked for a quick word, Osborne replied: “Relieved!”
He added: “I was surprised he was odds-on in a handicap, but we bought him because of his split mark and it worked.
“The beach is very different to the English all-weather, so there’s always a doubt, but that has taken the heat off.”
Osborne and O’Neill swiftly doubled up after the highly-rated Waqaas obliged as the 5-4 favourite in the Hibernia Steel (Q.R.) Race.
O’Neill said: “The lads are here to enjoy themselves, so it’s great for them. They were very good to give me the rides.”
And the trainer completed his hat-trick as Monumental Man – bought out of Michael Attwater’s yard after winning a seller at Lingfield last week – struck at 10-1 under champion jockey Colin Keane in the Bohan Hyland & Associates Handicap.
“We’ll be back next year, the boys love it. It’s an annual event for us and there’s going to be no shying away,” Osborne added.
The Melbourne 10-owned pair of Prosecution and Rippling Waters were out of luck in the opening Gilna’s Cottage Inn Maiden as 4-1 shot Bay Of Skaill struck gold for trainer Joe Murphy and jockey Gary Carroll.
“She’ll be back here next year, we’ll find something for her and maybe the Melbourne 10 might want to buy her!” joked Joe Murphy junior.
Cyrus Dallin justified 9-4 favouritism in the Scotch Hall Shopping Centre Claiming Race, trained and ridden by Denis Hogan.
Osborne’s Pulsating was second, with his other runner Kody Ridge withdrawn after getting loose before the start.