It was a bad day at the office for Lionel Messi against Iceland.

In what looked a fairly straightforward opening game for Argentina, they struggled at the hands of the smallest country to appear at a World Cup. Sergio Aguero gave the South Americans the lead but a Alfred Finnbogason equaliser arrived just four minutes later.

The biggest moment of the game, though, came from Messi when he had the opportunity to restore Argentina's lead from the penalty spot.

It's no secret that the Barcelona star doesn't have the greatest penalty record yet everybody watching still expected him to find the net.

However, it wasn't to be with Hannes Halldorsson - a director and handball player outside of football - plunged to his right and made the save.

Poor Messi performance vs Iceland

The miss cost Argentina victory and sparked a huge reaction on social media, not helped by Cristiano Ronaldo's breath-taking performance against Spain the day before.

Messi has been publicly reassured by his manager and teammates after his disappointing showing and now Jose Mourinho has had his say.

Working as a pundit with Russia Today, Mourinho made a very good point about the whole incident.

Mourinho reacts to Messi's performance

“No, when you miss a penalty in the World Cup, in the moment when the team needs a goal, that affects," Mourinho noted.

“He was trying, the one against one [defender], the one against two, the one against three... it was difficult for him, in spite of that he hit a few shots…

"Messi’s actions were always outside the box, he was trying, dribbling, shots….

“Probably even in superman, even in super players, they are humans, they have feelings and I think the penalty [miss] affected him."

You're not wrong, Jose.

There was a clear frustration within Messi's game, both in his struggles to break down the Icelandic defence and in his reaction to the penalty miss.

Messi, like Mourinho says, is human and it was an anomalously poor performance from a player who can seemingly go weeks without putting a foot wrong.

How Messi and Argentina react to the disappointing Iceland result will say a lot about their chances in Russia this summer.

Games against Nigeria and Croatia are next for the South Americans.

And if Euro 2016 is anything to go by, opening a tournament with a 1-1 draw against Iceland isn't the worst omen in the world.

How far do you think Argentina will go in Russia? Have your say in the comments section below.