He's done it, then. He's proven it.
Quite what he had to prove and why he had to prove it is up for debate, but that seems like something for another time.
Lionel Messi, the best footballer the world has seen since his countryman Diego Maradona, and probably ever, has got his hands on the one thing he didn't have.
Champions Leagues, Copa America, Ballons d'Or. All will feel insignificant to Messi as he lifts the World Cup, a trophy that - although sullied by its presence in Qatar - should signify such enormous achievement for a team, but has rather been usurped by a sense of personal achievement due to the noise surrounding this final.
This was Messi vs Kylian Mbappe, of course. The two superstars, old and new, who ply their trade for Qatar's most visible sporting venture prior to this past month.
That was all everyone was interested in, it seemed, with the images of the pair beaming back at you from all angles prior to this final.
But having seemed as though he was emphatically going to win the war for so much of the 90 minutes, Messi will be the first to tell you that this wasn't all about him, and that Argentina's success is all down to a superb collective effort from the pitch to their fanatical supporters in the stands.
Ever since that false start of an opening game against Saudi Arabia, a match that seemed to be played entirely in Argentina's heads and not the Lusail Stadium, the South Americans have had to manage their emotions during this run to the final. And they haven't always done that very well.
Because at 2-0 up and cruising this World Cup was won, Messi had his moment and Mbappe was kept quiet, largely by the combination of left-back Nahuel Molina and midfielder Rodrigo De Paul stationed in front of him, both demonstrating Atletico Madrid grit on the grandest of stages.
They weren't alone either.
Brighton's Alexis Mac Allister was superb in the first half, as was the slightly more celebrated Angel Di Maria and the midfielder Enzo Fernandez, who has suddenly appeared on several transfer radars in the past month.
For so long Argentina were going to win this, their hard-working players were going to get Messi to the status he has long craved, only for Mbappe to do what has come naturally to Messi for so many years. Change games.
Messi would have recognised that and respected it, even if Mbappe's celebration in his direction after his thrilling second was a little on the nose.
He took that though, absorbed it and then thought he'd won it when he almost funnelled the ball over the line in extra-time, only for Mbappe to hold his nerve again.
We went to penalties, which some say is a lottery but others look deeper. Emi Martinez made Aurelien Tchouameni look over to his left when he threw the ball away.
Bad sportsmanship? Probably. Extracting an advantage wherever you can find one? Definitely.
Argentina won this shootout and this competition as a team, even if we'll talk about their main individual for years.
We'll talk about Mbappe for years too. He'll have other moments.
Messi's greatest one has finally arrived, but he had his mates to thank for it.
