Arsene Wenger once said Daniel Karbassiyoon had huge ability and that on the few occasions he played his attitude and approach were always impressive.

Indeed, Karbassiyoon scored on his debut in a 2004 League Cup match against Manchester City, which was all the more remarkable given that he came on as a left-back for the final 12 minutes.

Arsenal’s wonderkid conveyor belt was at that point producing players like Cesc Fabregas and Robin van Persie – but, critically for Karbassiyoon, it also generated the Premier League’s two finest left-backs for many years in Ashley Cole and Gael Clichy.

‘Danny’ became a regular feature at Highbury as a spectator of Arsenal’s Invincibles side and, despite encouraging performances in the Gunners’ League Cup campaign, he was sent out on loan to Ipswich for the 2004-2005 season.

A chronic weakness in his knee, coupled with the robust nature of British football, then took its toll on his youthful frame.

On October 27 2004 he took an assist from Fabregas to score for Arsenal in front of 50,000 people, and 10 games and two clubs later he was released by Burnley in 2006 and never played football again.

There is no next page to the story of most professional footballers. For many, the talent that could have seen them play at the very top does not always collide with the fell clutch of circumstance.

Karbassiyoon’s story is not tragic. He is blessed with supportive parents back in the USA and has a more than able surrogate in Wenger. He is still employed by the man he knows only as The Boss.

The first American player to play for Arsenal, Karbassiyoon is now one of their most respected scouts in that continent and is credited with finding bright prospects such as Joel Campbell and Gedion Zelalem.

The fragile youngster who left America with an Arsenal scarf hanging above his bed is now a man, built and purposeful. He has no regrets over what could have been after that night in Manchester.

“To make it at a club you have to play 100 games. There’s nothing you can do in one game to make your mark,” he said.

“Living on that one moment isn’t enough and players who believe it is soon start to struggle.

“I knew there was so much more to do. I had to be in training the next day because I hadn’t played enough minutes in the match to qualify for a day off.

“It’s how people react that defines them. I saw guys at Arsenal who played in the first team and then didn’t want to play in the reserves after that.”

The perfect start often leads to false promise – fame and recognition curse many young players who can’t deal with their new recognition. For instance Federico Macheda, who memorably scored on debut in 2009 to give Manchester United victory over Aston Villa, is now a free agent.

It is easy to see why Karbassiyoon makes such a good scout. Wenger has said that the player who has won everything, stayed in top hotels and made fortunes is not often ready to travel second-class to watch football in difficult conditions.

Those who have the intelligence and motivation without the career are arguably far more valuable.

Arsenal want great footballers but they also want great attitudes, which may explain the ridicule directed by Gunners fans towards Nicklas Bendtner when he proclaimed himself the greatest striker in the world.

“To find these qualities at Arsenal we look at how a player conducts himself on the pitch,” Karbassiyoon explained. “How does he react to a setback? Or missing a great chance? Or going 1-0 down?

“Is he still going to fight or is he going to give up because his efforts aren’t worth anything right now?

“If you’re good enough, you’re old enough – that’s Arsene Wenger. Cesc Fabregas was the perfect example of that. Patrick Vieira got injured and Cesc got chucked in at 17 years old.

“He was good enough to assess any situation and not many guys at that age can do that. On his debut, no-one could get near him. He was playing against grown men and ran the show.

“The Boss is able to look at young players and know when they’re ready to make the jump into the first team because nothing can prepare you for playing in a full stadium. You either sink or swim. He’s great at judging whether or not players are able to be thrown into that.”

In recent years, Wenger’s youth policy has come under greater scrutiny as people question whether the conveyor belt that produced so many starts has started to assemble cheap knock-offs in light of Arsenal’s failure to win a league title since 2004.

To Karbassiyoon, the inevitable comparisons between the Invincibles and other Arsenal sides only prove that success cannot be bought.

“What made the Invincibles special was the mentality of the players,” he said. “When you look at the money that is spent by managers now, they’re able to build their dream team.

“But the mentality of that Arsenal side every day showed they were winners. What helped was this team had more than one leader.

“Sol Campbell led at the back and Kolo Toure led through his actions. He wasn’t spouting orders at you but he inspired you by the way he played the game, chasing any ball. It’s hard to find that now.”

Despite the abrupt and premature end to his career, Karbassiyoon would trade nothing for seeing his name on an Arsenal shirt, or walking out of a tunnel onto the Highbury pitch that, as a child, he watched on television 6,000 miles away.

“At Emirates Stadium there’s something called the Spirit of Highbury,” he added. “It’s a giant monument to every player that ever played at Highbury. It’s a team photo which starts in black and white and transitions into colour.

“I’m in that photo and seeing that alongside so many Arsenal legends is a feeling that will never leave me.”