On a summer evening in 2004, Brian O'Rourke was tidying up, preparing to leave Oakham School in Leicestershire where his Ireland Under-17 side had just wiped the floor with England Under-15. As he began accounting for each member of his squad, he noticed one, Eoin Morgan, out near the middle, talking to the opposition coach - Paul Farbrace. O'Rourke stopped and fixed his gaze.

"I thought, you know, those two aren't chatting about the weather," O'Rourke remembers. "There was something going on. The penny dropped at that stage."

Depending on who you ask, it was this conversation that set everything in motion: a move away from home, begin his qualification period, get settled with a county - Middlesex's 2nd XI coach had made overtures the year before Farbrace, now England's assistant coach, had his chat - and, eventually, play for the national team. But the truth is, those aware of Morgan's intentions for his career in the game - none more so than O'Rourke - knew only English cricket could match his ambitions. On Saturday, Morgan will walk out at Hagley Oval for his 200th ODI.

It will be his 177th for England since making the switch official in 2009, and 78th as captain. But the journey that started with 23 ODIs for the Boys in Green began at Ayr, in a European Championship Division One match against Scotland in August 2006. It was a debut in all but name for Morgan, who by then, aged 19, was an established force.

He was always the kid playing a few age-groups above his own, losing nothing but maybe a few inches in height with every level he stepped up. Even his coaches would joke that he was something of a know-it-all: the school-kid who relished taking a teacher down an avenue where he could show them up. Only Morgan was not doing it to flex his muscles, he genuinely believed, even as a 14-year-old, that he had parts of the game sussed.

On a trip to Denmark, he ran O'Rourke - his youth team coach at Ireland and Leinster - through his plans for playing spin. "You should have heard it. He had a simple philosophy that one of the first six balls from a spinner was going back over his head. I said, 'Geez Eoin, now, would you not just see what the wicket's like?'

"He looked at me and said: 'No, Brian - it's definitely happening. I don't know which one it's going to be, but it's going over long on.' Invariably, it went."

The above highlights traits that haven't changed in Morgan over the years: unwavering belief in his processes, stubborn as hell. He's loyal, too. His former team-mate and childhood friend Gary Wilson describes their friendship as one that could go months without a phone call yet, at the first sign of turmoil, Morgan would drop everything and jump on a plane. A characteristic he and others say has been forged in a home environment that offered him unwavering support wherever he went. "It definitely comes from his family," says Wilson. "They're very loyal people."

"Moggy was a state. I'm pretty sure if he reacted that way today, he'd probably get the boot!" William Porterfield on how Eoin Morgan reacted to being run out for 99 on ODI debut

During an Ireland age-group tour to the Netherlands, the Morgan family - father, mother and siblings - piled into a camper van and drove to watch Eoin, who was captaining the side. "It was brilliant," remembers Wilson. "They would make him food at lunch in the camper van. So he wouldn't eat the food at the ground, he'd go and get a fry up from his parents in the camper van. No one else could get away with that! Brian tried to pull him up on it but he was like, 'well, I want this food so I'm going to have this food.' He didn't see a problem with it and, to be fair, neither did we. Not when he'd come out and lash a hundred."

One was lashed during the 2006 Under-19 World Cup, too, as Morgan scored 338 runs - the second highest, after India's Cheteshwar Pujara - at an average of 67.60 just to ensure the rest of the international game knew who he was. He bowled a bit too back then, especially during the 2003-04 Under-19 World Cup, sending down 47 overs with a batch of white balls that swung around corners. "No one could control them," recalls William Porterfield, who led that side. "So after a couple of games, Morgs took the new ball and was bowling away-swingers to a seven-two field."

"He was pretty effective. In fact, I remember one of the games, he had a go at me. He'd bowled eight overs in a row and I was going to take him off to save a couple of later. He was like, 'Nah, I'm staying on to bowl ten through!'"

Porterfield's ODI debut also came in that match in Ayr, though his nerves were far greater than Morgan, who had already represented the full Ireland side in 27 matches spread across three first-class, 15 List A and nine games that fall within the margins, such is the inexcusable triviality of "status" in the international game. Not only was this Morgan's debut, it was only Ireland's second official one-day international. "The ODI status was a huge deal," says Porterfield. "Not just for us, as players, but it was huge for the team."

Eoin Morgan at the crease during his first ODI for England Getty Images

Memories from the game are hazy, but the scorecard paints a vivid picture. Scotland won the toss and elected to field first and, having come in at No. 3, Morgan held the Irish innings together with a 99 that, with the help of Kyle McCallan's unbeaten 43, dragged Ireland to 240 for 8. The pitch - "a dog's dinner" by this point - saw Scotland skittled for 155 to hand Ireland a debut win by 85 runs. The clearest image from the day, to many, was the aftermath of Morgan's dismissal: run out for the eighth wicket.

"He'll probably tell you it was Kyle's fault," quips Porterfield. "Moggy was a state. I'm pretty sure if he reacted that way today, he'd probably get the boot!"

Morgan was in tears as he walked off, hurling out a few expletives as he crossed the boundary before items of his kit went flying as he approached the changing room. The opportunity to score Ireland's first ODI hundred was taken away from him.

The honour would eventually fall to Jeremy Bray, against Scotland in January 2007. Morgan eventually became the fourth, notching a century against Canada in Nairobi a month later.

That would be his lot for Ireland, with 10 centuries for England wiping away whatever residual dismay that 99 might have festered. While Morgan walked off thinking he'd missed a chance at a ODI hundred, no one else - team-mates, coaches, the opposition - saw it as an opportunity spurned. "The hundred for him would have been good personally, but it'd be good for Irish cricket, too," says O'Rourke. "He set the standard for Irish cricket.

"Irish cricket is striving to be in a better position, with Test status, that we won't lose a player like Morgan again. But for someone from Ireland to have had the career that he has had, it doesn't half fill you with pride"