ATLANTA -- Ninety minutes before kickoff at Mercedes-Benz Stadium, the first roar went up from the crowd, or at least, those who had already taken their seats. Out on the pitch, nothing was happening. But the fans had caught their first glimpse of Lionel Messi on the stadium's giant, wraparound screen, as he walked smiling into the arena alongside teammate Rodrigo De Paul.

In theory, this Copa América opening game between Argentina and Canada was played on neutral ground. In reality, the home of MLS' Atlanta United and the NFL's Atlanta Falcons became the home of La Albiceleste, as they won 2-0 on the night.

Everywhere you looked, inside and outside the stadium, there were blue-and-white shirts. The stadium announcer's attempts to get some pro-Canada chants going prematch were met with bemused silence.

This crowd was here to see Argentina and Messi. An hour after his arrival, as the world champions came out to warm up and the starting XI was read out, Messi's name was met with another roar. There were more cheers when he scored in shooting practice. Argentina are not all about the 36-year-old Messi anymore -- they have too many good players for that, molded into a functioning unit by coach Lionel Scaloni -- but this is still Messi's team.

Canada, making their Copa América debut, did their best to spoil the party. They played a hugely impressive first 45 minutes; captain Alphonso Davies was a lightning-quick threat down the left, Jonathan David and Cyle Larin were a handful up front. But they did not take their chances, and they lived to regret it.

When Argentina's breakthrough came, in the 49th minute, it was a Messi moment of inspiration, the kind of pass that only the eight-time Ballon d'Or winner can see, let alone execute. His defense-splitting pass played in midfielder Alexis Mac Allister, whose clever, brave touch -- with goalkeeper Maxime Crépeau rushing out -- allowed Julián Álvarez to make it 1-0.

After that, two golden chances for Messi to finish the contest. In the 65th minute, he was in on goal. Crepeau saved his shot well. Messi picked up the rebound, danced around Crépeau, and then had his follow-up blocked by defender Derek Cornelius. Messi laughed, a look of disbelief on his face. The crowd chanted his name. Fifteen minutes later, Messi was again one-on-one with Crépeau. This time he scooped his shot wide.

The Copa América has been everything for Messi. It was the scene of his lowest ebb, retiring prematurely from international football in 2016 after missing in the penalty shootout defeat to Chile in the final in New Jersey.

"For me, the national team is over," he said that day. "I've done all I can." It wasn't, and he hadn't.

Months later, he was back, and by 2021, Messi was winning the Copa in Brazil, beating the hosts in the final. It was a weight lifted, the beginning of Argentina's new golden era. Eighteen months later, they were champions at the World Cup in Qatar.

This is, in essence, still that same team. Eight of these XI started the World Cup final in December 2022. Of those that didn't, Marcos Acuña and Leandro Paredes came on as substitutes. Messi, two years older and now based in Florida with Inter Miami, remains the heartbeat. Starting against Canada means he has now played in seven Copa América tournaments. No player has featured in more games in this competition, 35 and counting.

Here, he faced Canada with the overwhelming majority of the 70,564 fans at the Mercedes-Benz Stadium cheering him on in what felt like a game being played in Buenos Aires, not Atlanta. It didn't seem entirely fair.

Still, the atmosphere was more celebratory than hostile. That was helped by an entertaining, open first half with chances for both teams. Canada's best were created by Davies -- Tajon Buchanan put one shot wide, David saw another blocked -- until Stephen Eustáquio's point-blank header was saved by Emiliano Martínez before halftime.

Then came Álvarez's opening goal, with just his second shot of the game. The pass that preceded it from Messi defied logic. Mac Allister hadn't even begun to make his run in behind when Messi played the ball. And yet there Mac Allister was on the end of it. Álvarez did the rest. All that was lacking now was a Messi goal. He didn't get it, with those two, surprising, frustrating misses, but he did get an assist, playing in substitute Lautaro Martínez with a casually brilliant pass to finish the contest and ensure the Copa América holders got off to a winning start.

The last kick of the game, a Messi free kick just outside the box, was saved by Crépeau. He hadn't scored. But he'd ended the game with a key role in both goals and five "big chances" created. Next up, Chile on Tuesday at MetLife Stadium.

"There's a bit of fear that it's all ending," Messi told ESPN last week. "I try to enjoy it. I do that more now, because I'm aware that there's not a lot of time left."

We don't know if this will be Messi's last international tournament. He has remained non-committal on making it to the 2026 World Cup, which will be mainly hosted in the United States. But it does seem highly likely that this is his last Copa América.

"It doesn't make much sense to think about when they're gone," coach Scaloni said on Wednesday, asked about Messi and teammate Ángel Di María. "Let's enjoy them now."

Those in the Atlanta crowd certainly did. And with this tournament just getting started, there's more to come.