It will go down as one of the greatest upsets in World Cup history and the result leaves Argentina with a mountain to climb if they are to reach the second round knockout stage.
Saudi Arabia stunned Argentina – and the entire globe – on Tuesday morning with a 2-1 victory that will reverberate across the world.
Albiceleste captain Lionel Messi had given the Copa América holders an early lead from the penalty spot but Saleh Al-Shehri equalised early in the second half. Just a few minutes later, Salem Al-Dawsari struck a sensational winner from distance to sink Argentina and end the side's 36-match unbeaten run.
Playing a brave and risky high defensive line, the athletic Saudis rode their luck in the first half. Three times Argentina had the ball in the net, only to be denied by an offside call.
But during a chaotic start to the second half, the Saudis swarmed all over Lionel Scaloni's team and scored twice as the Arab nation beat the South Americans for the first time in five attempts.
In a first half dominated by Argentina, it initially seemed to be only a matter of time before the Albiceleste sliced through the Saudi back-line. That condensed the game into a sliver of green turf around the halfway line as the Saudis happily allowed Argentina's back four to pass the ball among themselves.
It seemed the Middle Eastern sidewere facing a long afternoon after VAR intervened to award a penalty when Saud Abdulhamid wrestled Leandro Paredes to the ground in the box at a corner.
Messi waited for goalkeeper Mohammed Al-Owais to dive to his left before cooly rolling the ball into the opposite corner.
But if the Saudis felt aggrieved at the technology, it would later help keep them in the game. Argentina thrice the ball in the net only to be denied by razor-tight offside calls, the first given by VAR.
There was no controversy about the equaliser three minutes into the second half, though, as Al-Shehri ran onto a touch from Feras Al-Brikan, beat Cristian Romero on the outside and slotted the ball back across goalkeeper Emiliano Martínez and into the far corner.
The sizeable Saudi contingent in the Lusail stadium – where the World Cup final will be held – exploded in joy.
Suddenly the Argentines were rattled and, five minutes later, the turnaround was complete.
Al-Dawsari's clever turn in the box beat two defenders before he shifted the ball past a third and rifled an unstoppable shot into the top far corner.
The crowd was going wild and Hassan Al-Tambakti punched the air in delight after his desperate sliding tackle denied Messi a clear shot at goal.
Every Al-Owais save, including a point-blank block from Nicolas Tagliafico's close-range prod, was greeted with rapturous cheers.
There was late drama after Al-Owais collided with Yasser Al-Shahrani and seemed to knock him out as his knee struck the defender's head.
Argentina had no answer and, despite playing almost 14 minutes of injury time, they felt short in the search for an equaliser.
"Sometimes all the stars are aligned," said Saudi's French coach Herve Renard. "Today all the stars were aligned for us."
"We made history for football," he added. "It will stay forever, this is most important. But we also have to think about looking forward. We still have two difficult games before us."
Defeat is a bitter blow for Argentina, who were one game away from equalling Italy's all-time record of 37 matches unbeaten.
Forward Lautaro Martínez said the loss – in what is likely to be the final World Cup of Messi's glittering career – hurt badly.
"It's clear we lost the game because of our own mistakes, especially in the second half," he said.
"In the first half, we should have scored more than a goal. But that's the World Cup. Now we have to rest and think about what's ahead. There are two finals [ahead] now."
The national team now faces two crunch matches to turnaround its tournament: this Saturday's match against Mexico and next Wednesday's clash with Poland. Game on.
Stadium: Lusail Iconic Stadium (Lusail)
Attendance (official): 88,012
Referee: Slavko Vincic (SLO)
Argentina: Messi (10th minute, penalty);
Saudi Arabia: Al-Shehri (48), Al-Dawsari (53).,
Saudi Arabia: Al-Malki (67), Al-Bulaihi (75), Al-Dawsari (79), Abdulhamid (82), Al-Abed (88), Al-Owais (90+1)
Argentina: Damián Martínez - Nahuel Molina Lucero, Nicolás Otamendi, Cristian Romero (Lisandro Martínez 59), Nicolás Tagliafico (Marcos Acuña 71) - Leandro Paredes (Enzo Fernández 59), Ángel Di María, Rodrigo De Paul, Alejandro Gómez (Julián Álvarez 59), Lionel Messi (captain) - Lautaro Martínez. Coach: Lionel Scaloni.
Saudi Arabia: Mohammed Al-Owais - Saud Abdulhamid, Hassan Altambakti, Ali Al-Bulaihi, Yasser Al-Shahrani (Mohammed Al-Breik 90+9) - Abdulellah Al-Malki, Mohamed Kanno - Salman Al-Faraj (captain) (Nawaf Al-Abed 45+4, Alamri 88), Saleh Al-Shehri (Sultan Al-Ghanam 78), Firas Al-Buraikan (Haitham Mohammed Asiri 89), Salem Al-Dawsari. Coach: Hervé Renard.