Unheralded Saudi Arabia notched one of the biggest shocks in World Cup history with a 2-1 win over Lionel Messi's Argentina thanks to a scintillating second half comeback.
On his fifth and final quest for the only major trophy to elude him, the 35-year-old Messi scored a 10th minute penalty in a dominant first half display where he and Lautaro Martinez also had three goals disallowed for offside.
But Saudi Arabia, the second-lowest ranked team in the tournament after Ghana, threw caution to the wind at the start of the second half, charging at Argentina's defence in front of a frenzied 88,012 crowd.
Saleh Al-Shehri squeezed in a low shot in the 48th minute while Salem Al-Dawsari curled in a scorching strike from the edge of the penalty area in the 53rd minute to leave Argentina and Messi looking utterly shell-shocked in the Group C opener.
Despite plenty of possession after that, Argentina were unable to penetrate Saudi Arabia, who were competing in their sixth World Cup but had never previously won an opening game.
The entire game was played in an extraordinary atmosphere at the Lusail Stadium, with Argentina's traditionally massive and raucous following matched by the thousands of Saudis who had come over the border to cheer on their team.
Both teams have Mexico and Poland to come, with Argentina needing an immediate reaction if Messi is to have a realistic chance of matching Diego Maradona's immortality in his homeland by bringing home the World Cup.
The result broke Argentina's amazing 36-match undefeated run and stopped them from matching the previous international record of 37 games unbeaten held by Italy.
Meanwhile, Denmark hit the woodwork in the second half as they were held to a 0-0 draw by Tunisia in their Group D World Cup opener that smouldered and sparked, but never quite caught fire at the Education City Stadium.
Against a backdrop of raucous noise provided by the thousands of Tunisian fans in the stands, Issam Jebali had a goal ruled out for offside in the 23rd minute but it was Denmark who provided most of the attacking football in the first half.
The Danes upped the tempo in the second, with Christian Eriksen firing a rasping left-foot shot that was saved by goalkeeper Aymen Dahmen in the 69th minute, and Andreas Cornelius hit the post with a header from the resulting corner.
Tunisia defended resolutely and threatened on the counter as the Danes struggled to break them down, and in the end their fans were delighted with a point that sets them up for their next game against Australia, while Denmark face France.
Poland's Robert Lewandowski missed a penalty - and his chance to finally claim a World Cup goal - in a 0-0 draw with Mexico.
Mexico played most of the attacking football in Stadium 974 but Poland won their penalty in the 56th minute when Hector Moreno pulled down Lewandowski only for the Polish captain to shoot too close to Guillermo Ochoa, who saved.
Mexico brought on Wolverhampton Wanderers striker Raul Jimenez as a substitute, capping his return from injury, but he failed to provide the breakthrough sought by coach Gerardo Martino.
The draw left Saudi Arabia top of Group C with three points.
Reuters
