Argentina were stunned by Saudi Arabia as their highly anticipated 2022 World Cup campaign began with a seismic Group A defeat by the 750-1 outsiders.
The Albiceleste, unbeaten in 36 matches over the past three years, went ahead with a 10th-minute penalty from captain Lionel Messi, looking to cap a wonderful career by winning the tournament at the fifth attempt.
But Argentina failed to build on their first-half dominance, having three further goals — one for Messi, two for Lautaro Martinez — ruled out for offside.
They were made to pay in a remarkable opening to the second half as Saudi Arabia first levelled and then went in front in the space of five sensational minutes.
First Saleh Al-Shehri surged past Cristan Romero and clipped a left-footed shot into the far corner before, in the 53rd minute, Salem Al-Dawsari spun round, swerved away from a defender and curled in a brilliant effort from the left edge of the area into into the top-right corner.
Argentina tried to find a way back into the game, but Saudi Arabia goalkeeper Mohamed Al-Owais made a series of saves from Nicolas Tagliafico, Messi and Julian Alvarez to seal one of the most remarkable results in World Cup history.
Saudi Arabia now have a chance of reaching the last 16 for only the second time as they prepare to face Poland next, while Argentina must pick themselves up before facing Mexico.