The game was watched by 18,624 people in person — with millions more watching in on television. Just over seven years previously, Larranaga’s last game as Ireland player-coach against Luxembourg in Tallaght was watched by a couple of hundred fans at best.

But Larranaga is adamant that he wouldn’t be where he is now if it wasn’t for his time managing Ireland.

“Part of the reason I got my first job in the States with the Erie Bayhawks in the NBDL [the tier below the NBA] was because I had two years’ experience as a head coach with Ireland.

"Those two years really helped me — even when I was talking to the Celtics,” admits Larranaga.

Larranaga was Ireland’s player-coach between 2007 and 2009 and played for this country for the guts of a decade on top of that. He qualified through his grandfather on his mother’s side — Vincent Lynch — who was born in Cork city but moved with his family to the States at the age of five.

Larranaga’s father Jim is a legend in college coaching — having coached 31 seasons and counting. He’s currently at the University of Miami but coached Jay for his four seasons as a player at Bowling Green State University.

When Larranaga’s time as a collegiate athlete was over — his Irish connection was to prove a huge advantage.

“When I was getting ready to go overseas to play basketball professionally, the Bosman Rule had just started to take effect.

"The fact that I was Irish meant that I qualified as an EU guy [as opposed to a US import, who were restricted] and it allowed me to play at a much higher level than I would have if I played with my American passport,” admits Larranaga who won a Spanish championship with Real Madrid in 2005 and Italian national cups with Napoli in 2006 and 2008 in a career that spanned 13 years with 13 different clubs.

“It’s part of the reason I always played for the Irish national team at every opportunity,” says Larranaga.

“I felt I owed a real debt to Irish basketball for what it allowed me to do in Europe. It was a tremendous honour — my parents came over for games and it was a huge deal.”

As a player, Larranaga was a part of Ireland’s greatest ever spell as an international team — securing a spot in the semi-finals for the European Championships.

A win in Finland — against a team featuring 6ft 11in NBA player Hanno Mottola — meant Ireland qualified to face the likes of Germany, Croatia and Macedonia.

It’s worth noting that Ireland only lost to Croatia by two points eight years ago. This summer Croatia finished fifth in the Olympics.

While Croatia were doing the business in Rio, Ireland’s national team had just reformed seven years after being disbanded and finished fourth in the European Championships for Small Countries. Still though, that night in June 2007 still makes the hairs on the back of Larranaga’s neck stand on end.

“That night in Finland was incredible. I remember after we won, looking at the likes of Adrian Fulton, Gareth Maguire and Damien Sealy.

"They were domestic players that had played forever for the Irish team, and to see the raw emotion of what it meant. It was incredible and by far the best thing that happened in my career. The bond we had as a group was special.”

Adrian Fulton was in the trenches alongside Larranaga for years and he confirms that bond is as strong as ever but gives the modest Larranaga a lot more credit for the win in Finland than he claims.

“Jay was fabulous that night,” says Fulton. “He had 29 points, and to deliver when all the expectations were on him was incredible. We had been so close for years but Jay really helped get us over the line. He never looked down on us for not playing professionally or anything like that.

“He still hasn’t forgotten the friendships. I was in the States on a school trip and I phoned Jay — and even though I hadn’t spoken to him in a while — and straight away he got us tickets and got us down on the floor and introduced us to players.

"It was amazing. He would go out of his way for you. He deserves every bit of his success and he’s had an incredible career.”

That career took Larranaga back across the Atlantic, where after two years honing his craft with the Erie Bayhawks in the development league, he got his chance to become the assistant manager at the legendary Boston Celtics.

That was in 2012 and the Celtics still had the likes of Kevin Garnett, Paul Pierce, Rajon Rondo, and Jason Terry in their ranks. Larranaga admits he was somewhat starstruck at the beginning.

“Everything I get to do... I can’t believe I get paid to do it. I have that ‘pinch-me’ feeling about 10 times a day every day. I get to work with the best athletes in the world, I go to Boston Garden as my office. In my first year I got to work with Kevin Garnett, Paul Pierce, and Jason Terry. They are three Hall of Fame players. Who gets to do that?”

After Larranaga’s first year — the Celtics decided to rebuild and traded away practically all of the big names and replaced head coach Doc Rivers with rookie coach Brad Stevens.

In the three years since, the Celtics have completely reinvented themselves as a young and talented squad, with Stevens’ reputation skyrocketing as a coach. In footballing terms, Stevens would be an amalgam of Jurgen Klopp and Thomas Tuchel — the hipster’s choice, if you will.

Either way the Celtics enter this NBA season — they’re 2-1 after three games — as the fourth favourites to win the championship.

Granted, they are fourth favourites in what many people consider a two-horse race between the superstar-laden Golden State Warriors and LeBron James’ Clevland Cavaliers but Larranaga is unapologetic in his confident outlook for the Celtics this year, especially after this summer adding four-time All-Star Al Horford to the mix of up-and-coming young players.

“Our goal is to win the championship,” he says. “I believe that our group have enough to get there and win the championship. People say the [Golden State] Warriors were unbeatable — and what happens in their very first game? They lost [by 29 points to the San Antonio Spurs].

“Adding Al Horford can help us do even better. The term that people use after meeting him is he’s an ‘adult’. You wouldn’t think that would be such a great compliment but in a sport where there is so much youth with guys coming into the league at 19 or 20 years old, it’s nice to have somebody who has the right focus every day.

"Our goal is to maximise our potential and we are never going to put a ceiling on what we can do as a team. Brad always says that — we are never going to put a ceiling on our success.”