Cristiano Ronaldo and Lionel Messi are the best two players in the world, there's no question about it.

Sure, it's plausible that Luka Modric was number one across 2018, but nobody really comes close to the mercurial duo when everything is considered.

Football fans have been spoilt by their remarkable performances over the last decade and the thought of both players retiring is almost unthinkable.

Nevertheless, that sad inevitability is creeping ever closer as Messi and Ronaldo stride into their thirties and the final years of their careers.

Don't get us wrong, Messi still has plenty left in the tank at 31 and Ronaldo's remarkable conditioning could see him play at a high level for the next half-decade at least.

Ronaldo and Messi in their 30s

But their ages are definitely having an impact on their transfer value, even if Ronaldo's €100 million move to Juventus would suggest the contrary.

However, considering the amount of questions raised about the fee and the fact his original release clause was actually €1 billion, his older age is clearly making some sort of difference.

As a result, when studies have been completed on the most valuable players, Messi and Ronaldo have finished a lot lower than they used to. 

Most valuable XI

And it turns out that neither player - despite their undoubted quality - makes the most valuable starting XI in world football by predicted transfer fee.

Transfermarkt constantly collect data about players to calculate their market value and offer a tool for football fans to keep an eye on the XI which would cost the most money.

Although the selection can be altered by changing formation, age or nationalities, the first result of their calculations still throws up some unexpected examples.

Take a look at the starting XI down below:

Kevin De Bruyne over Messi, anyone?

It's definitely interesting that Jan Oblak takes his place between the sticks ahead of David de Gea or even Alisson Becker, but the defence seems reasonably predictable.

Saul Niguez is without doubt the most surprising player in the team, especially when you consider he has only scored three goals for Atletico Madrid this season.

Four Premier League players feature with the aforementioned De Bruyne -  boasting an eye-watering value of £135 million - appearing alongside Virgil van Dijk, N'Golo Kante and Harry Kane. 

The main reason that Ronaldo and Messi miss out is, well, Paris Saint-Germain.

The extortionate prices surrounding Neymar and Kylian Mbappe ensure their places in the team with the latter, despite his tender age of 19, boasting the highest figure of all at £180 million.

All that said and values aside, any other XI and nobody would ever leave Ronaldo and Messi out.

Who do you think is the most valuable player in world football? Have your say in the comments section below.