Gwent native Mike Ruddock was five years on from leading Wales to a Six Nations Grand Slam when he took over the Ireland Under-20s in 2010.
In his four years in the job, his sides would include the likes of Tadhg Furlong, Josh van der Flier, Jack Conan, Iain Henderson and Finlay Bealham.
Furthermore, after taking up the reins at All-Ireland League outfit Lansdowne, he would nurture young talents James Ryan, Ronan Kelleher and Dan Sheehan as they made their way in the Leinster academy.
“Back in Ireland, I would tease the lads in Lansdowne that I put a bit of Gwent into the Irish pack,” Ruddock told BBC Sport NI.
“So many graduated through the under-20s, I’d tell them, ‘that’s a Gwent pack, not an Irish one.’ Eventually they threatened to ban me if I kept going about it.”
Ruddock would work with Beirne for both the under-20s and Lansdowne.
“My big memory of him initially is what an incredible athlete he was,” remembered Ruddock.
“There wasn’t a huge amount of muscle mass on him in those days. He was lean, he was strong, and he was brilliant over the ball.
“Engine-wise, he would run all day and he was very adaptable. Six or lock, he gave me an extra line-out jumper and another jackler.”
But while a number of his peers went on to quickly make their mark on provincial set-ups and then the international stage, Beirne struggled to make his own breakthrough.
Adding muscle to his frame was certainly one goal – it was Ruddock who gave Beirne the nickname ‘long dog’ in a nod to another lean lock, former Welsh international Luke Charteris – while developing his line-out calling was another.
In truth, however, the main obstacle in his path was the sheer depth in Leinster’s forward pack. Still, he remained determined.
“The biggest thing I remember is how laidback he was,” said Ruddock.
“But once you scratched under the surface, he was hardworking.
“Sometimes we’d finish training at Lansdowne and he’d hop straight on his push-bike and go off delivering pizzas to pay his way. You could see that he really wanted to do something with his rugby.”
