The South American side was expected to brush aside its opponent, ranked 48 places below them in the world standings, and fans had come in droves to watch Messi put on a masterclass in what he says will be his last tournament.
But the Argentine captain was overshadowed by arguably the biggest upset in World Cup history and, as Saudi Arabia celebrated its win, Messi trudged down the tunnel with a face of thunder.
The seven-time Ballon d’Or, who has yet to lift the World Cup trophy, didn’t hide from the embarrassment though.
As many of his teammates stormed past reporters on the way to the team bus, Messi was one of two players to speak to the media – the other being goalkeeper Emiliano Martínez.
“There are no excuses. We are going to be more united than ever. This group is strong, and we have shown it,” he said.
“It is a situation that we haven’t gone through in a long time. Now, we have to show that this is a real group.”
In the grand scheme of the tournament, a loss in the opening match isn’t necessarily the end of the world – after all, Spain won the 2010 World Cup after losing its opening match of the tournament to Switzerland.
Argentina will still likely qualify for the knockout rounds if it wins both of its next games against Poland and Mexico but the defeat was felt particularly hard at home.
Words such as “nightmare” and “inexplicable” were used by Argentine media reacting to the shock result which leaves its side with no margin for error.
“The truth? Dead,” Messi said when asked about the team’s morale. “It’s a very hard blow because we did not expect to start in this way.
“We expected to get the three points that would have given us calmness.
“My message to the supporters is to have faith. We won’t leave them stranded.”
Those supporters have gathered in Doha in force and had seemingly outnumbered Saudis inside the Lusail Stadium on Tuesday.
Thousands in blue and white shirts sang Messi’s name as they made their way to the game and continued to celebrate their hero as he graced Qatar 2022 with a penalty in the opening 10 minutes.
But, at 35, Messi is not at the peak of his powers and the Saudis were successful in smothering his space at every opportunity.
The Argentine players still looked for Messi almost every time they got the ball. If he didn’t demand the ball himself, Messi would often orchestrate the play by pointing to where he wanted the ball to go.
But despite flashes of brilliance, he couldn’t find the space in order to change the game. At the final whistle, the Argentine fans were slumped in their seats and it was the Saudi supporters chanting Messi’s name ironically.
While leaving the venue, CNN heard fans joking with volunteers and FIFA officials, asking them if they had seen Argentina captain Lionel Messi “after he went missing all game.”
See hilarious moment a Saudi soccer fan tears a door from frame during surprise upset
Doha was abuzz with Saudi supporters long into the evening and flags were still being waved into early Wednesday morning.
Jubilant fans leaving the stadium took the Metro back into downtown Doha where celebrations continued, many singing until their voices started to break.
Others were busy reliving the experience on their phones, watching highlights of the goals and looking at footage of celebrations from back home.
Saudi Arabia’s King Salman bin Abdulaziz Al Saud subsequently ordered a national public holiday for Wednesday as the world came to terms with such an unexpected result.
Amid all the excitement, though, Saudi manager Hervé Renard demanded his side focus on building a successful campaign.
Saudi Arabia faces Poland in its next game before playing Mexico.
“We made history for Saudi football, it will stay forever, this is the most important,” he told reporters after the match.
“But we need to think about looking forward because we still have two games, very difficult for us.”
As for Messi, he will have another day in the sun at Qatar 2022.
What feels like the end of the world today will be a distant memory if he can inspire his side to victory against Mexico on Saturday.
There are thousands of fans in Doha praying their hero can once again be the answer and confirm his status as the greatest player of all time.