Jose Mourinho believes Kylian Mbappe's age and "incredible" ability makes him more valuable than even Lionel Messi and Cristiano Ronaldo.
And it is his youth that former Manchester United manager Mourinho views as the critical difference when comparing his worth in the transfer market to Barcelona captain Messi, 31, and Juventus talisman Ronaldo, 34.
"For a player like Mbappe, when you speak about the future, you don't need to say what he's going to be like in five years' time, in 10 years' time," Mourinho told beIN Sports.
"Just focus on now. He's absolutely incredible.
"I think going by his age and [and considering] the age of Cristiano, of Messi, [both] over 30, Neymar is 27... when you go to the market level and age is also a factor, I think he's the most valuable player in the world.
"In a hypothetical transfer, he's the most expensive player in football now.
"In terms of his qualities, [he is] unbelievable. One word is enough. It means everything."
Speaking at a media conference on Monday, Les Bleus boss Didier Deschamps endorsed the young forward's maturity and ability to cope with close attention from opposition players.
"He has such abilities that he may face some tough challenges on the pitch. He's ready to deal with that kind of thing," Deschamps said.
"I cannot say that he had disproportionate reactions so far. He reacts because it's never pleasant.
"He deals well with those situations though. He's used to it. It's something he has experienced since the beginning of his career and he will be subjected to this his entire career because of what he's able to do on the pitch."