United States and Barcelona youth Konrad de la Fuente said he was totally awestruck when he first met Lionel Messi, but told ESPN he thinks NBA icon LeBron James is the bigger star between the two transcendent athletes.

De La Fuente joined Barcelona's academy as a 12-year-old in 2014 and remembers his first encounter with the Argentina international vividly.

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"He [Messi] was having an interview at La Masia and I was there," De La Fuente said. "When the interview was over I went to go take a picture of him.

"And as I'm walking up to him -- I'm with two of my other friends -- I'm like 'Oh, it's Messi, it's great.' I'm like almost shaking. And I asked him if I could take a picture and he goes: 'Yeah,' and I have my phone in my hand, and I'm looking down at my hand is trembling.

"It was crazy. I've never felt like that in my life."

Seeing Messi around the club has become more commonplace for De la Fuente, who still has that first photograph, although it's still not without the occasional awkward interaction -- like when he turned up to train with the first team for the first time.

"It's not that I'm used to [seeing Messi now] but I still get a little starstruck but not like that," the Barca B winger said.

"The first time I trained with the first team, I got into the locker room and I turned to go into it and run into someone. And I looked and I see it's Messi.

"I said: 'Hi,' and shook his hand and everything. And then as I walked past him I said: 'Oh my God I just [ran into] Messi.' But there was just that moment and that's it. And then it was just normal."

Despite being close to the record Ballon d'Or-winner, De La Fuente said he believes NBA star James to be the bigger athlete.

"My favourite player is LeBron," he added. "He's my idol.

"I'm just a LeBron fan, probably the biggest fan in the world. Its incredible how much of a fan I am with him. I really admire him, I want to be like that, in the soccer world. In that sense he's bigger than Messi for me."

De La Fuente has represented the U.S. youth teams since the under-16 level. He has not received his first cap with the senior team but has high ambitions for the future.

"My goal is to win a World Cup," he said. "I think it can happen.

"If we continue to grow in our clubs in Europe, I think we can do something special."