Captained by Lionel Messi, arguably the greatest footballer of all time, Argentina were expected to make short work of the unfancied Saudis before a deep run in the competition, and came to Qatar as second favourites to lift the trophy behind South American rivals Brazil.
But many thousands of Saudi Arabian fans packed the Lusail Stadium in Doha to cheer their team to a remarkable comeback victory, as a quickfire double of second-half goals by Saleh Alshehri and Salem Aldawsari eclipsed Messi’s early penalty.
"One of the biggest shocks in FIFA World Cup history," tweeted the official account.
Saudi Arabia’s public holiday applies to all employees in public and private sectors, as well as students.
The Saudi ruling dictator Crown Prince Mohammed bin Salman was visible at the opening game of the tournament, sitting alongside much-maligned Fifa president Gianni Infantino. Saudi Arabia are bidding for hosting rights to the 2030 World Cup.
Argentina’s tournament is now already at risk of collapsing and they face a battle to emerge from Group C as one of two qualifiers for the knockout rounds. They take on Mexico next on Saturday, after Saudi Arabia play Poland earlier in the day.