Only last month, Zlatan Ibrahimovic explained in characteristically boastful fashion that he wouldn't retire until he saw someone better than him.
"So, [that's why] I'm still playing," he quipped in an interview with UEFA's official website.
However, while Zlatan the public persona continues to exude confidence and invincibility, Ibrahimovic the man has never really hidden his insecurities and vulnerability, particularly when it comes to facing retirement.
He still plays for the pure love of the game, of course, but it goes beyond that for him. He openly admits that he is addicted to the "adrenaline" that comes with playing top-flight football.
He has pointed out that he and his peers are "programmed" from an early age, and thus utterly dependent on the routines which form the foundations of a professional footballer’s career.
"Every day we do the same thing," Ibrahimovic explained. "We wake up, we prepare, we train, we eat, and we rest. The next day, it's the same thing.
"For 20 years, you do these things, and you get adrenaline from them.
"So, when suddenly you stop, you don't have this agenda, you don't get the adrenaline anymore.
"And when it stops, you have to take it from there and begin from zero and start something new."
That is a terrifying prospect for the 40-year-old Ibrahimovic, who made his Malmo debut as a teenager in 1999.
He only first realised just how much he would miss the game when he spent seven months on the sidelines with a cruciate ligament injury sustained in 2017 while playing for Manchester United.Getty
"I understood then that football is everything for me," he told reporters at San Remo last year. "I fear quitting because I don't know what awaits me afterwards."
A post-football future, though, is something that Ibrahimovic is now going to have to think long and hard about.
On Tuesday, it was confirmed that the Swede will be out of action for at least another 10 days with the nagging knee issue that forced him to sit out last weekend's 0-0 draw with Torino.
The news is particularly worrying, as Ibra had only just been trying to work his way back to full fitness after an Achilles tendon issue forced him to sit out all four of Milan's Serie fixtures in February.
Indeed, he had only managed 31 minutes of action before breaking down again, meaning he has featured in just under 40 percent of the Rossoneri's matches this season because of injury.
And it is worth pointing out that he has not been hit with fractures, bumps and bruises, but rather inflammation, aches and pains – the telltale signs of wear and tear.
He retains a fine physique for a footballer, not least because he is still the first man to arrive at training, and the last man to leave.
It's simply that his body is breaking down and, as Milan coach Stefano Pioli says, "He just has to live with his ailments."
Milan do too, for now at least.
Ibrahimovic's current contract expires at the end of the season but the hope was that he would sign a one-year extension.
However, the question is now being asked if that would really be the right move, for either party.
When fit to play, Ibrahimovic remains a formidable proposition.
As Brazil legend Ronaldinho told Sportmediaset, "Zlatan is a phenomenon: at his age, he's still better than several youngsters! He can play until he's 50. He doesn't lack quality."
That latter statement is undeniably true, in fairness.
Despite missing 16 of Milan's 41 games through injury this season, he remains their joint-top scorer in Serie A alongside Olivier Giroud and Rafael Leao, with eight goals.
However, that says as much about the Rossoneri's misfiring forwards as it does Ibrahimovic's enduring excellence.
Having propelled themselves to the top of the Serie A standings, thanks in no small part to massive wins over title rivals Inter and Napoli, Milan's position is looking increasingly perilous because of their lack of a cutting edge.
Consecutive scoreless draws have allowed Inter to draw to within two points of Pioli's side while still having a game in hand, which the Nerazzurri will play later this month in Bologna.
The pressure, then, is very much on Milan going into Friday's clash with Genoa at San Siro, and Ibrahimovic's absence will once again be keenly felt.
The veteran forward is a true leader on and off the field for one of the youngest squads in Serie A.
His experience, professionalism and, believe it or not, willingness to help those around him has seen him play a major role in the Rossoneri's reemergence as a major force in Italian football over the past two years.
Given his considerable influence on the dressing room, the value of an increasingly injury-prone Ibrahimovic to Milan is difficult to quantify.
There is no denying, though, that if he does sign a renewal this summer, it will be on significantly reduced terms, with the centre forward presently one of the club's highest earners, on €7 million (£5.8m/$7.5m) a season.
Paolo Maldini & Co. could well feel that he is worth retaining simply because of his role model status.
Ultimately, though, Ibrahimovic will not want to play the part of a glorified cheerleader.
“It would be sad to see a champion like Ibra not getting enough playing time or not being up to the task," former Italy international Luca Toni told the Gazzetta dello Sport earlier this week.
"A player like him should go out on top, where he has been his entire career."
Ibrahimovic himself would doubtlessly agree. He will want to finish with a flourish, and on his own terms.
Of course, you don't always get what you want in football, not at his age.
Francesco Totti knows that only too well. He didn't suffer anything like as many physical problems as Ibrahimovic during his final season at Roma but he barely featured anyway.
Totti felt he could still cut it in Serie A; then-Roma boss Luciano Spalletti thought otherwise.
Milan, Maldini and Pioli could well reach a similar conclusion with Ibrahimovic, even if it would be for slightly different reasons.Getty
"When you don’t play consistently, especially at a certain age, the body doesn’t rest but gets rusty," Totti explained in an interview with the Gazzetta on Thursday.
“When you are accustomed to being introduced as a substitute, you lose rhythm. Your mind knows what to do, but your legs are not quick enough. You know you are better than the others, but the body can’t be in the game.
“Right now, Zlatan is not playing and I can imagine his difficulties because his body is a demanding machine.
"From what I can see from the outside, he wants to remain on the pitch as much as Milan want to keep him.
"The problem is not technical, the problem is his playing time.
“I know what he feels, I think I know the questions he is asking himself, and about his desire to fight with the reality."
Ibrahimovic certainly won't want to give in.
As David Lagercrantz, the co-author of I Am Zlatan has pointed out in the past, Ibrahimovic's whole career has been driven by the desire to prove people wrong, which is why he has continued doing extraordinary things even after turning 40.
"It shouldn’t actually be possible," Jacob Johansson told FIFA.com of his former Sweden team-mate's remarkable longevity.
"He’s been battling with injuries recently, but we all know Zlatan. Anything is possible when he’s on the pitch. That’s why he’s a superstar."
And why Ibrahimovic is going to find it so difficult to walk away.