Saudi Arabia stunned the world into silence on Tuesday by defeating the mighty Argentina in their World Cup opener.

To say the result was 'off-script' would be quite the understatement.

Saudi were 500/1 to win the match after Lionel Messi converted from the spot in the 10th minute and gave La Albiceleste an early advantage.

Nevertheless, the enormous underdogs epitomised what the World Cup is all about and put forth a valiant display to fight back and secure a historic 2-1 victory.

We're pretty sure 99.9% of the watching population could barely believe their eyes.

However, one man who may have been slightly less taken aback is Sergio Aguero.

The former Argentinian hitman actually warned his team of the threat from Saudi seven months prior, whilst on a live stream.

In what is a fascinating piece of analysis to watch now, Aguero identified three key tactical points that Lionel Scaloni (Argentina's manager) needed to focus on, whilst he watched Saudi in their Asian qualifiers.

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What did Aguero say?

"High pressure, look where the defender is pressuring," Aguero began as he watched the match.

"High pressure, careful with this. Watch out Scaloni! I'm giving you all the details, so you don't need to say anything. Show this video of mine to the boys."

Aguero then identified 'controlling the offside' as the second big requirement for playing against Saudi.

"Look here, it's important to play as a line. Look at the midfielder where he is pressuring, wow, risky, very risky."

The final point the Manchester city legend concluded from watching the match was to control the number 10.

"The 10 is good, he's got quality. Watch out for the 10. Guys, write this down, this 10, Al-Dawsari. You have to control the 10."

VIDEO: Aguero's Saudi warning

Maybe Scaloni and his Argentina team were complacent heading into the encounter.

They were carrying the momentum of a 36-game undefeated streak into the tournament and probably expected to sweep Saudi aside with ease.

But one man that certainly wasn't sleeping on their threat was Aguero and full credit to him for that.

La Albiceleste will need to bounce back in their next game when they take on Mexico this Saturday night if they want to maintain any hope of winning their group.