David Beckham Says This Has Been ‘Biggest Challenge’ of His Career (Exclusive)

• David Beckham reveals the “biggest challenge” he’s faced in his career and why it’s “the most rewarding”
• The soccer star talks about Lionel Messi’s impact on soccer and Inter Miami CF
• Beckham tells PEOPLE how he believes soccer can grow its popularity in the United States

Soccer star David Beckham has faced many challenges throughout his illustrious career. 

A World Cup red card that resulted in global backlash, pressure to perform under intense scrutiny throughout his relationship with former Spice Girl, and now wife, Victoria Beckham, and his public struggles with Obsessive-Compulsive Disorder (OCD) to name a few. Still, none of these trials compare to Beckham’s current role as co-owner of Inter Miami CF soccer club.

“When we first announced it, I thought we’d have the team up and running in a few years,” Beckham tells PEOPLE at an Inter Miami CF Tailgate to introduce Ninja’s FlexFlame™ 5 in 1 Outdoor Cooking System.

But the process of building the fútbol club, the accompanying soccer academy for youth players and the now-under-construction stadium took quite a bit longer. “It’s been the biggest challenge that I’ve had in my career and my business life, but it’s been the most rewarding,” he says.

One such challenge that has resulted in unimaginable rewards has been signing legendary player Lionel Messi to the team. “I always promised that I would bring the world’s best players here, and when you make those promises — especially here in Miami — you have to keep it,” Beckham says, while sampling select grill creations from the La Familia fans. “But I never thought in my wildest dreams I would bring the greatest player to have ever played the game.”

The effect of Messi’s presence on the team is almost unquantifiable. “Everything has changed for us. We’ve quadrupled everything on one signing — the difference is incredible. The difference on the field off the field. On the field is obvious because obviously he’s quality, and… the other young players are gaining knowledge from him, but also, they’re getting better from them which is one of the reasons why you bring these players in,” Beckham says.

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But the “Messi effect” extends well beyond the pitch. “Off the field, the amount of interest we’ve had globally as a club, the numbers that we have coming in, the new stadium that we’re building, the new sponsors that come in and are interested — it’s all of those things.”

Messi’s fame has even drawn non-traditional soccer fans like Kendall Jenner to recent games. “I enjoy people wanting to come and support and come in to see our team — it’s what I always wanted, it’s what I always envisioned…people want to see the greatest of all time play,” he says.

But at 37, Messi can’t play forever — as much as Beckham and all soccer fans wish he could. “I hope he never retires but…. we’ll be prepared for that day, and Leo will always be part of this club,” he says.

As to when that might happen? “Ten years would be nice. Ten is a nice round number,” Beckham adds with a laugh. 

The real reward of this experience, David explains, has been the soccer academy he built with the club. “We’ve got six members of the Academy on the squad, and we’ve got four players that are playing a lot of the games which makes me really proud because the Academy is what I really, really cared about when I first came to Miami,” he says, adding, “That’s what’s going to grow the sport in this city but it’s also what’s going to grow the sport in America.” 

“I’ve always said that one day the national team will compete to win the World Cup. They have to — the size of this country, the coaches that are in this country, the facilities, all of those opportunities. But it all starts at the grassroots level, and that’s the one thing that I really care about.”

The only piece missing from the puzzle? A chance for American fans to see David “Bend it like Beckham” in real life. “I would love to play truthfully, trust me,” he says. “I miss it every single day. I get very jealous.”