Then the man that everyone came to see put his mark on this tournament. Lionel Messi's here. His stunning goal in the 2-1 win over Bosnia and Herzegovina, exchanging passes with Gonzalo Higuain before swerving through challenges and curling into the corner, is just his second at a World Cup. And it may well be one of the best of all after the final reckoning.
This was, of course, his big buildup. Messi at the Maracana - that's where iconic football moments are made. And for a long time it was weighing not only on his mind but on that of the team. He was statistically the worst player on the pitch in the first half, losing possession 15 times.
But coach Alejandro Sabella made a tactical change, and the shackles were removed. A different player emerged.
Messi and strike partner Sergio Aguero were thrown together in an unconvincing 5-3-2 formation from the start by Sabella, forced upon him due to injury concerns over Higuain and Fernando Gago. The set-up wasn't conducive to incisive attacking football. Aguero completed six passes in the entire first half, while Messi looked disinterested in finding the space necessary so deep in Bosnian territory.
But Sabella has unquestionably unlocked Messi's ability at national team level like no other coach has, and he resorted to the formation that worked so well for him, and his superstar, during qualification.
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The resulting 4-3-3 with Messi drifting off the front instantly rejuvenated a team that had previously looked stale. Messi was then collecting the ball facing the goal rather than with his back to it, and had able runners in Aguero, Angel di Maria and Higuain.
Messi admitted as much to Argentine TV after the match, as well as what his strike meant to him personally.
He said: "In the first half we were too deep and that hampered our attack. The second goal was a relief for everybody and especially for me, because it was good to score."
This was, of course, by no means a vintage Messi display. Passes still went astray and there's still much room for improvement in his performance and that of the entire unit. But that goal's skill and poise, and his coach's decision after just 45 minutes to discard the tactic he had been operating with, are both significant. He was running, linking, jinking, tackling. A proverbial performance of two halves.
There is work to do yet. Bosnia and Herzegovina showed ambition in the last 15 minutes and Vedad Ibisevic's goal meant more pressure on the scoreline than there ought to have been. But the match will be remembered for one moment and Argentina's boisterous fans hope their hero can enjoy a World Cup that his talent, and ultimately legacy, deserve.
The Barca star added: "The Maracana was great, I had no doubt it would be like that. We keep working towards the dream."
With Sabella's tweaks and Messi's poise and determination returning, he might be back here again next month. That is his dream - his nation's dream.