Lionel Messi said Argentina's shock loss to Saudi Arabia was a "very heavy blow" but vowed the South American champions would bounce back from the defeat.
"It's a very heavy blow, a defeat that hurts, but we must continue to have confidence in ourselves," Messi said after Argentina crashed to a stunning 2-1 loss in Group C, reports Al Jazeera.
"This group is not going to give up. We will try to beat Mexico," he added.
Messi lamented Argentina's shock second half capitulation against Saudi Arabia but said he was not surprised by the threat from opponents 48 places lower in the world rankings.
"It's a situation that this group of players has never been through, it's been a while since we suffered such a tough blow, we didn't expect to start like this," Messi told an Argentinian media outle.
Starting his fifth World Cup, Messi had opened the scoring with a 10th minute penalty and Argentina had three goals disallowed for offside in a free-flowing first half.
But in the second half, "in five minutes of mistakes that we made, we went 2-1 down and then it was really tough and we lost organisation and started punting the ball," he said in comments broadcast by Todo Noticias.
Messi said his team knew Saudi Arabia, despite being the second-lowest ranked team in the tournament, could hurt them.
"We knew they were a team who would play if we let them...They did not surprise us, we knew they could do that."
Playing in his fifth and probably final World Cup, Messi has the weight of an entire nation's expectations on his shoulders.
One of the greatest players of all time, this may be his last chance to lift football's greatest prize, which his predecessor as Argentina's idol Diego Maradona did in 1986.
"We have to go back to the basics of who we are. We have to think about what's coming next," said the seven-time Ballon d'Or winner.
Argentina now have to focus on beating Mexico and Poland in their next group games in search of the only major title that has eluded Messi in his otherwise glittering career.
However, this is not the first time. Argentina started the World Cup journey by losing the first match six times before. In one such tournament, they even managed to reach the finals.
Argentina was the runner-up in the first World Cup in 1930 but they were eliminated after losing 2-3 to Sweden in the first match of the next 1934 World Cup. Then in 1958, they lost 1-3 to West Germany in the first match. Then in the first match of the 1974 World Cup, Albicestes again lost 2-3 to Poland. In the first match of the 1982 World Cup, they lost to Belgium 0-1.