EAST RUTHERFORD, N.J. - If the prospect of facing Lionel Messi was not already formidable enough, he sat down in front the press on Friday, the day of his 29th birthday, and came out fighting.

The normally quiet superstar - too quiet for some, most notably Diego Maradona - gave a rare media conference at MetLife Stadium, and treated those present to an even rarer outburst. And by his discreet standards, an outburst is what it was.

On Thursday he sent the Argentine press into overdrive when he posted a picture on Instagram of himself and best friend Sergio Aguero (who had put on a comically forlorn face for the moment) sitting on a grounded plane at Chicago airport, above a caption which said: "what a disaster the AFA are, my God."

The AFA, of course, is the Argentine Football Association. Its at best poor and at worst crooked administration almost resulted in Argentina being pulled out of the tournament before it had even begun, but Messi's frustration came to a head thanks to a delayed flight to New York ahead of Sunday's Copa America Centenario final against Chile.

The governing body quickly put out an official statement insisting the delay was due to bad weather, and that flights were scheduled by the Copa anyway. It was clearly flustered by criticism from its own star, but an extra half an hour on the tarmac is not the main issue.

Messi has had enough. Questioned, inevitably, about his feelings towards the AFA, he gave a somewhat threatening response.

"Perhaps I made an error in the moment, with the final so close, as we want to think about that. The delay, waiting on a plane again... Now is not the moment. I could respond to that [AFA] statement, but I prefer to leave it there and think about the final.

"We arrived here like this, without resolving what is going on in the AFA, and it never affected us, we're just thinking about the Copa and nothing is going to change that. The one thing, and it's the minimum, is that we can travel well, that we can rest and we can prepare well for the game. What comes from outside doesn't affect us. We can't do anything about that.

"Things have been happening for a long time and none of us said anything. We try to reach our goals. I said it at that point because that's how I felt. The national team, one of the world's best, needs to have the best. I said what I said and that's it. But it's not because of what happened [Thursday], there are so many things that have been stacking up, the time has come that something has to change, not just for for us now, but for what comes next. We have to have the best, as is what happens with all the other national teams.

"I would like to think about the final of the Copa. After we will talk and I'll tell you everything that I think, feel, see and what I was thinking at that moment."

This is not the type of player to play games with the media, dropping hints only to further his own personal interests. He is no Zlatan Ibrahimovic, who insisted he will unleash "the bomb of the summer" only to unveil a new clothing line. He is no Cristiano Ronaldo, who said he was "sad" to get more money out of Real Madrid. Perhaps the Chicago run-way is to Messi what Saipan was to Roy Keane.

Messi is the humble superstar. He is the epitome of a footballer who 'lets his feet do the talking.' In that sense, he's already said plenty this summer.

The 19-minute hat trick against Panama was unforgettable. He put the ball through the keeper's legs against Bolivia as his impudent performance hinted at a desire to please the crowds that have come out in force to see him. He was accused of showing off on that night but the next time he put the ball through a goalie's legs he did so to equal his country's all-time scoring record. He had already put on a superb assist for Gonzalo Higuain in that quarterfinal against Venezuela, and racked up another later on with a bamboozling first-time pass.

In the semis he undid the U.S.'s best-laid plans with another fine assist and then a free kick of the utmost quality. Perhaps one of his best ever goals, and one that put him out in front of Gabriel Batistuta in the scoring charts.

So he has done his talking on the pitch. He has been screaming his lungs out all over the States.

The AFA were not the only ones to get an earful yesterday, either.

Sepp Blatter, the disgraced former FIFA president, 'revealed' recently that Messi had said "I am the best, but I am not a champion" after losing the World Cup final.

"It's a lie," the Barcelona man dismissed, instantly.

There is no doubt, however he may have put it into words, that he will be driven by that defeat to Germany, just as last year's loss to Chile in the Copa America will provide unrivalled motivation when the two sides meet again at the MetLife Stadium on Sunday.

Chile managed to keep him quiet as it won its first ever trophy on home soil 12 months ago, but now he is performing at a far higher level than in either knockout phase in the past two summers. He is at the top of his game right now.

And he has form at the MetLife, a wonderful, European-style football cathedral. "I have great memories of that game, when we beat Brazil and I scored three goals. It's a very nice stadium to play at."

Those goals, scored at the same time as Germany played Portugal at Euro 2012, were spectacular, but, by coming in a friendly, were somewhat overshadowed.

This time, in a final, there is nothing to snatch the headlines away from him, and there is nothing to say he couldn't score another hattrick, given the form he is in.

This match could finally deliver Argentina's long-awaited international triumph, the country's first since 1993, and one that could seal a legacy for its talisman. Judging by everything else these past few weeks, now both on and off the pitch, Messi is a man on a mission to make it happen.