Every success story has to start somewhere. In the case of Karim Benzema, it was catching the eye of the man whose judgment of players draws collective scorn from all four sides of Ibrox. The most talked-about teenager in European football owes his discovery to none other than Paul Le Guen and if the Lyons striker wrecks the Champions League ambitions of Rangers on Wednesday night, it will be an inescapable irony.

While it has cost Rangers millions of pounds to clear up the mistakes left behind by the Frenchman, his legacy to Lyons is vastly different. The French champions could make £40 million if they can tempt Real Madrid, Arsenal, Chelsea, Barcelona and AC Milan into an auction for Benzema this summer. Not bad for a kid from a council estate in the Lyons suburbs who cost nothing after being spotted at the age of nine.

Benzema’s prolific talent in front of goal would probably have been impossible to miss. However, it is Le Guen who has to take the credit for fast-tracking the player in his final season in charge at Lyons in 2004-05. It was the former Rangers manager who gave Benzema his debut at the tender age of 17 and suggested the five-year contract for the player that will earn the French club a fortune when they cash in on his talent.

The 19-year-old has already scored 16 times this season and has three goals to his name in eight appearances for France since being given his debut by Raymond Domenech last March against Austria, where, naturally, he found the net.

Arsène Wenger believes that Benzema will be one of the stars of Euro 2008 next summer, by which time he hopes to have him in Arsenal’s colours but Lyons’ rude financial health in posting revenue in 2007 of almost £100 million - in France, clubs are not allowed, by law, to be in debt - means that they are in no rush to sell their new teen idol.

Indeed, Jean-Michel Aulas, the club president, brushed aside some of the frenzied speculation about Benzema’s future by declaring that he will not leave Lyons until the European Cup is paraded from the balcony of the city’s Marie. That is a lot of responsibility for a kid from a drab housing scheme whose Algerian parents struggled to make ends meet.

Benzema was spotted by Lyons scouts playing for his youth team, Bron Terraillon, in 1996 at the tender age of nine and was quickly signed up to the club’s excellent academy. His ascent through the youth system was swift and prolific. France recognised that gift, too. Benzema scored 20 goals in 35 appearances between under16s and under18s and helped his country to win the European Under17 Championships in 2004. Le Guen, who had been noting the development, promoted the teenager to his first-team squad and in January 2005. Benzema came off the bench to make his debut in a league encounter with Metz, making an instant impact by setting up a late winner for Bryan Bergougnoux.

Le Guen did not allow the moment to go to Benzema’s head. He trained with the first team but made only six appearances. However, he continued to bang in the goals for the Lyons under18s. By the time Le Guen left in May 2005, for his sabbatical year followed by the wretched six-month tenure at Ibrox, he had highlighted the potential of Benzema to Aulas.

Sadly, Le Guen’s successor, Gérard Houllier, was not as enthusiastic. In the same way that Le Guen jettisoned Kris Boyd - bequeathed to him by Alex McLeish - so Houllier marginalised Benzema for his own favourites, John Carew and the Brazilian striker, Fred. If Benzema played at all, it was out wide.

Indeed, the youngster has a bluntness that evokes Boyd, when he considers his value to any team. “My best position? Centre-forward, without a doubt,” he told France Football recently. “For two season, the coach at Lyons [Houllier] only played me out wide right, or left. It meant I had to defend and hardly allowed me any scoring efforts. However, the only thing that interests me is scoring goals. It is there, in my head. It is an obsession.

“I only wanted one thing out of this season and that was for the new coach [Alain Perrin] to play me in my real position. For most of this season, I’ve played up front and I’ve scored. I knew that Fred and Milan Baros could also occupy this position but I am not scared of competition. I have trained now with the first-team squad for three years and I have gone beyond being considered as a youngster. At 17 I still was and even at 18. But today, I am thought of as just another first-team player. I’ve matured. I’ve known big moments in the Champions League and won two French titles but I no longer want people to think of me as the youngster just breaking through - I am just a player who wants to progress at Lyons.”

It was felt that Houllier did not advance Benzema’s progress as well as he could. The former Liverpool manager restricted the wonder kid to just 13 league appearances in 2005-06 - Benzema also scored on his Champions League debut against Rosenborg - and in 2006-07 he played 21 times and scored five goals, including the one against Dynamo Kiev that allowed Lyons to progress into the last 16 of the Champions League.

However, when Houllier bought Baros, his erstwhile signing at Anfield, from Aston Villa, and played the sullen Czech Republic striker ahead of the local boy, that was the straw that broke the camel’s back. Or, more accurately, Bernard Lacombe.

Lyons’ director of football was manager of the team a decade ago and as one of the most celebrated strikers in France, with over 300 goals for club and country, embracing two World Cup finals, Lacombe feels he knows a natural finisher when he sees one.

Lacombe is the man Aulas trusts implicitly in football matters. Houllier’s shelf-life at the Stade Gerland was brief once he favoured Baros. Perrin knows he has to give Benzema centre stage. “Bernard told me that he expects me to get 15 goals,” Benzema said. “It’s not only been me, though. With the likes of Juninho, Kader Keita, Kim Kallstrom and Ben Arfa we’ve got a lot of talent in the side.”

Benzema will turn 20 on December 19. Rather than having a cake, he could celebrate with a prize. Just 24 hours earlier, he could be named France’s footballer of the year for 2007 at an awards ceremony . Rangers need to guard against him blowing out their European dreams, too.