PSG's Lionel Messi lays behind wall for free kick, Neymar asks: 'What are you doing there?'

Ever since Lionel Messi joined Paris Saint-Germain from Barcelona in the summer in one of the most monumental transfers of all-time, soccer fans across the world have been waiting for him to light up the Champions League in his new club's colours.

While he certainly did just that in Tuesday's group match against Manchester City, scoring a sublime goal in his side's 2-0 win over the Premier League champions, few expected to see the jarring sight of Messi tasked with being the footballing equivalent of cannon fodder.

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PSG seeking to protect their clean sheet while facing a free kick in second-half stoppage time, Messi was deployed to lay down behind the defensive wall in order to block any crafty low shots from creeping beneath it.

Many players have been asked to quite literally put their bodies on the line over the years, with it becoming a more regular sight in recent seasons since the trend gained popularity at the elite level in South America before making its way over to Europe's top leagues. But never before has a player of the calibre of Messi, with six Ballon d'Ors at home on the mantelpiece, got down on the turf ready take one for the team.

For one night only, arguably the greatest player ever to grace the game became the world's most famous 5-foot-7 draft excluder.

We have never seen other players at the elite level, such as Messi's longtime rival Cristiano Ronaldo, stoop so low (in the very literal sense). Although, standing at 6-foot-2, the strapping frame of Ronaldo is definitely of more use standing in the wall itself.

Obviously, the sight of Messi hunkering down behind the PSG blockade took many by surprise, not least his teammate Neymar, who was just as shocked as the rest of us to see his old Barca buddy sprawled out beneath him.

Indeed, Neymar later took to his Instagram stories to poke fun at the situation by posting a photo of Messi on the deck and quipping: "What are you doing there, Lionel?"

Pundits were similarly baffled, with former Manchester United defender Rio Ferdinand even blasting the "disrespect" of making such a venerated player adopt the blocking role. Ferdinand argued that the rest of the PSG team should have been falling over themselves to relieve Messi of his defensive duties and take his place on the ground, telling BT Sport:

"The moment [PSG coach] Mauricio Pochettino asked him to do that at the training ground, someone should've gone in there and said, 'No, no, no, no, no, no.'

"This doesn't happen to Leo Messi. No, no, no, no. You can't. It's disrespectful, I wouldn't have it. If I was in that team, I'd have to say, 'Listen, I'll lay down for you.'

"Sorry, I couldn't have him laying down like that. I can't see it. He don't get his kit dirty, that's not what Messi does."

Mass confusion reigned on social media as fans struggled to get to grips with the concept, though the irony of having to use Messi as a human barricade at the foot of the wall wasn't lost on everybody.

On the other side of the equation, Messi's willingness to muck in and do the dirty work in the interest of protecting his side's winning margin was impressive. It happened shortly after the 34-year-old had scored PSG's second goal of the night against City, curling a delightful finish home from the edge of the area after playing a one-two with Kylian Mbappe to register his first goal for his new club.

PSG have got themselves a man who can do both, and in doing so he helped his side recover from their disappointing 1-1 draw at Club Brugge on matchday 1 to go top of Group A and leave City in third place after two games.

There can no longer be any debate: Messi is the G.O.A.T (if, rather than "Greatest Of All Time," that acronym stands for "Ground Obstructor and Attack Thwarter."