On This Day: Teenage Messi shows glimpses of genius on Barcelona debut

Watch: On This Day - Lionel Messi shows glimpses of future genius on Barcelona debut

This article is part of Yahoo's 'On This Day' series.

He’s arguably the greatest footballer to have ever lived, but on this day 18 years ago, Lionel Messi was just a prodigious teenager looking to start his career.

A diminutive, straggly-haired 16-year-old coming on as substitute, Messi first appeared in Barcelona’s first team in a friendly against Jose Mourinho’s Porto, on 16 November, 2003.

Messi had enrolled at Barcelona’s famous La Masia youth academy aged 13 after relocating from his native Argentina - but Barca fans watching his debut three years later could not have dreamt of the impact he would have on the Catalan side in the years to come.

Barcelona’s then-manager Frank Rijkaard substituted Messi on with around 15 minutes remaining in the friendly in Portugal. He was 16 years, 145 days old, and wore the No.14 shirt rather than his now iconic No.10.

While the teenage Messi showed glimpses of the growing genius which would turn him into a global sporting icon, his first appearance was a goalless one as Barcelona lost 2-0.

He produced a handful of trademark weaving runs forward, and even spurned a couple of goalscoring chances as his first team debut ended unsuccessfully.

Coaches at Barcelona were still impressed though, and Messi was fast-tracked into the club’s reserves.

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His stock rose further when Brazilian Ronaldinho - then the club’s flamboyant star player and fan favourite - declared Messi would become an ever better player than he was.

Team-mate Ludovic Giuly, meanwhile, was similarly effusive - saying that Messi would regularly ‘destroy us all’ in training even as a teenager and called him an ‘alien’ due to his unfathomed ability.

Messi, on the other hand, was just happy to have been involved against Porto.

Describing his first Barca appearance, he later told ESPN: “November 16 is a very special date for me, because that’s when I was able to make my childhood dream come true–it was a very happy day for me. I’d fought hard to make that moment happen and it was really special.

“I remember that we were training with the Youth A team and when it finished, [team co-ordinator Josep] Colomer talked to me about a few things and then told me that I would be travelling with the first team.

“He told me that I should just go and enjoy the game and the experience, but when I came back I should concentrate on the Youth A team.”

Watch: Fans overjoyed as Messi and Ramos introduced to PSG fans in Paris

He would have to wait another 11 months to make his competitive league debut for Barcelona, but nearly two decades later, Messi has won it all.

With a record six Ballon d’Or wins, 35 trophies (including 10 league titles and four Champions’ Leagues) and a host of scoring records thanks to his staggering 474 goals for Barcelona, it’s no wonder fans now consider him the greatest current player in the world and one of the best ever.