Messi and Ronaldo don't appear opposite each other too much ever since the latter's move to Juventus in 2018, but they'll face off again this evening with Barcelona taking on Juve in the Champions League.

Author Simon Kuper joined Joe Molloy on this evening's OTB, to discuss how Messi and Ronaldo have come to dominate both the game and the way we speak about it over the last 15 years.

And while the pair have essentially owned the Ballon d'Or for more than a decade, they seemingly have very little in common. The bulk of their careers have been spent either side of the El Clasico divide, Ronaldo is the athlete, while Messi is the artist. Ronaldo is loud and brash, while we know very little about Lionel Messi the man.

There's a strong perception that Ronaldo craves adulation. The Juventus striker feeds off the praise and headlines, while Kuper says Messi's craving is much different. Messi is content with his name, but adores power, something Kuper says has eventually caught up on both the player and the club.

"I think he (Messi) has always known that he was the best, it's not something he ever doubted.

"The Barcelona staffer who drove him to his first training session with the first team when Messi was 16, this tiny kid gets into the back of the car and the staffer says 'Are you nervous?', hoping to reassure him. Messi says, "No".

"He joins the first team - these are players famous around the world - and he's completely unbothered, he doesn't know who they are, he doesn't really care, he doesn't watch football on tv, he's never heard of many famous footballers. H just assumed from the start he's going to be great," Kuper says.

"What Messi craves is not adulation. that's of zero interest to him. It's power. He wants Barcelona to buy the players and play the way he wants to play. And Barcelona - especially in the early years when he didn't talk so they kind of guess what he wanted - have spent 15 years trying to do just that.

"And so FC Barcelona gradually becoming FC Messi, which I think in the end no longer works out the way it did for 15 years. That's he wants. He wants them to do exactly what he wants them to do."

The power of presence both Messi and Ronaldo have on the pitch is undeniable, even with the pair in their mid-30s.

Kuper says one similarity between the pair is the fear their teammates have of them.

"I think Messi is now quite scary, and the other players are mostly quite scared of him. He's now playing with players who hero-worshipped him growing up and so thy give him the ball instantly, they give him the ball too much, they give him the ball when he's not in a dangerous position, partly because they're scared of him.

I interviewed Frenkie de Jong last year and he said: 'You always look where is Messi, so that when you get the ball you can give it to him'. Xavi and Iniesta had more status and were already great players by the time Messi came up, were able to hold on and switch the ball to the left wing, and build there, and then switch to Messi when he was one on one.

"Now his role in the team is too dominant, he's too scary. You see that with Cristiano especially playing for Portugal where he often plays with quite poor teammates, that when somebody hits the ball too wide and Cristiano will look at him aghast and in horror, and the guy just melts into the ground."