Messi becomes World Cup all-time leading scorer - how has he stayed at the top?

"Playing at a high level at our age, you have to pay close attention to your life hygiene - how you sleep, your diet, and taking care of your body, because that's the thing you rely on for work.

"The key thing is still having the desire, the motivation, the passion, to keep going."

Messi is not the only global sports superstar to have continued laying down gauntlets for younger rivals into their late 30s - tennis' Novak Djokovic being perhaps the most impressive example in recent years.

But doing so requires a combination of relentless dedication to physical fitness and unerring self-belief.

"Players know themselves inside out by that age, so there's not a lot left to teach them about how to manage as they get older," says Michael Caulfield, a sports psychologist working in professional football for more than 20 years.

"From a physical point of view, they take advantage of every breakthrough in sports science.

"But mentally, it's about whether they have the capacity in their minds to deal with the daily grind. They have to be willing to spend the whole year working hard on the same things, and if you've been doing that for 25 years, that takes huge self-discipline.

"They have to maintain the sheer will to go through the rehab process after injuries when they know they've already won everything.

"All the top athletes I've ever known, they're all willing to try and go back one more time, because they love doing what they do.

"It's the same reason you still see Bruce Springsteen or Madonna touring - it is completely intrinsic to who these stars are."

Messi's incredible ability with the ball at his feet has helped compensate for any lost athleticism over the years.

"Coming into this World Cup, I pretty much wrote Argentina's chances off because I didn't think he could carry on [at that level] for another one," says Wayne Rooney, part of the Manchester United team which lost the 2009 and 2011 Champions League finals to Barcelona and Messi, who scored in both and was man of the match in the latter.

"The one thing age can never take away from players is their ability with the ball. You put him around the penalty box and he has the ability to do things others can't.

"It'll be interesting to see whether it can last the rest of the tournament. [If it does] then it wouldn't surprise me if we see him in the next World Cup for Argentina as well."

'Messi loves football like a little boy'

Image caption,

Messi was in tears after scoring the opener in Argentina's first match against Algeria, and in the days afterwards his family published a statement revealing that his father is "dealing with a health-related situation"

Generally considered a reserved and humble character, Messi has occasionally demonstrated a will to revel in his personal stardom, including when he hoisted aloft his own shirt in front of Real Madrid fans after scoring an injury-time winner in an El Clasico victory in 2017.

"When he crosses the white line, he is a very different person," says his former Barcelona team-mate Cesc Fabregas in the BBC iPlayer documentary Rivals: Messi vs Ronaldo. "He wants to win at any cost."

That relentless desire to succeed can underpin a sports career long after a star like Messi has achieved everything their discipline has to offer, as can the sheer love of the game of itself.

"Athletes always think there's something left to achieve," says Caulfield. "They're wondering if there is something they haven't quite mastered yet.

"But more than anything they want to keep feeling that childlike joy of doing what they love. You see Messi still doing keepy-ups or a rondo, and he still loves football like a little boy."

Messi's incredible display drew stark contrast with his perennial rival, Cristiano Ronaldo, who is playing in his sixth World Cup with Portugal.

The 41-year-old made very little impact in his side's opening draw with DR Congo, and those who know him best believe Messi's display will have played on his mind.

"Ronaldo will have been fuming," Rooney says. "Even at 41 he will still be expecting to be top goalscorer. But that attitude is part of his own greatness. The two of them have spurred each other on.

"They have this self-belief and arrogance, in a good way, where they know they what they have done, have nothing to prove, and it's up to the likes of Mbappe and Haaland to prove they can take over."