The Green Falcons' 2-1 defeat of a Lionel Messi-led team hitherto unbeaten in three years was the greatest result for an Arab nation since Algeria defeated West Germany in 1982.
That handed Saudi Arabia positive publicity at a time when many around the world still associate the kingdom with autocratic rule and rights abuses.
Video of young Saudis dancing joyfully in delight and waving the national flag outside the stadium, and of others leaping around televisions at home, offered a glimpse of a Saudi Arabia often buried by negative headlines.
"Argentina: We Are Saudi," proclaimed the front page of Okaz, an independent Saudi daily newspaper, as the kingdom's media erupted in national pride.
In the football world, the result catapulted French coach Herve Renard, who once worked as a cleaner between training, to fame along with his little-known and entirely home-based team.
It also erased at a stroke the hurt of humiliating starts to past tournaments, including 5-0 and 8-0 losses to Russia and Germany in 2018 and 2002 respectively, reviving fans' hopes that the Green Falcons can restore regional hegemony.
Qatar had portrayed its success in securing the World Cup as one for the wider region. And beyond Saudi borders, other Arabs appeared to be celebrating the victory.
Social media images quickly spread of fans in Iraq, Yemen, Tunisia and Jordan leaping up and down and cheering as the game finished.
"A thousand thousand congratulations Saudi Arabia," said Amin Hassan from Sudan on Twitter.
Perhaps the biggest significance, however, was for Saudi Arabia's international image. It faced widespread diplomatic ostracism after the 2018 murder of Saudi journalist Jamal Khashoggi at its consulate in Istanbul.
Though critics will decry it as more "sportswashing" in a country where the United Nations says 17 men have been executed in the last two weeks, Saudi Arabia's efforts to establish themselves as a big mover in world sport will inevitably be assisted by one of the World Cup's greatest upsets.
Already this year, the Saudis had hosted their second Formula One Grand Prix in a row.
And England's Newcastle United have been flying in the Premier League since they were bought by a Saudi-led consortium.
RENARD THE HERO
Even before Tuesday's match, Saudi Arabian Crown Prince Mohammed bin Salman had taken a seat next to football body FIFA's president at the World Cup opener, looking like a man back at the international top table.
His nation still has many religious and social strictures seen as extreme outside the region and is largely intolerant of political dissent.
Still, Saudis of many political stripes say outsiders often fail to look beyond the kingdom's politics to see the more complex reality of a country with 35 million inhabitants and a rich cultural history - a reality that may be a little more visible after Tuesday's victory.
Saudi Arabia has a proud record of domestic football competition with fierce rivalries among the big Riyadh and Jeddah clubs that include repeated winners of the Asian Champions League.
Saudi Arabia is the second-most crowned team after Japan in the Asian Championship, with six appearances in the finals and three titles, the last of which was in 1996. They have also won the Gulf Cup three times and the Arab Cup twice.
Their previously most notable World Cup moment was when striker Saeed Owairan skipped past half the Belgian defence from his own half to score one of the best goals in the 1994 tournament in the United States.
"Congratulations to our leadership, congratulations to the Saudi people... the future will be better, God willing," said Saudi football association president Yasser al-Misehel.
The Saudis will be indebted to Renard.
He joined after Japan dumped them out of the 2019 Asian Cup, beginning a long-term project for this World Cup and next year's Asian Cup, also in Qatar.
Of the starting lineup in the loss to Japan back then, only goalkeeper Muhammad Al Owais, midfielder Salman Al Faraj, striker Salem Al Dawsari and defender Yasser Al Shahrani remained for Tuesday's game against Argentina.
In contrast to neighbouring Qatar, who have 10 naturalised players in its ranks, Renard found talent in local leagues, including Abdulelah Al-Maliki, the cornerstone of his defence.
Saudi players tend to stay at home given the local league's financial clout. Al Dawsari, who scored the winning goal against Argentina, renewed his contract with Al-Hilal last season for 52 million Saudi riyals ($14 million) for four years.
