are reportedly ready to pay Franco Mastantuono's big-money release clause. But the River Plate wonderkid's entourage are believed to have informed interested clubs that there is only one destination on his mind.

Mastantuono does not turn 18 until August, but he is already into his second season as a regular fixture in the Argentinian top flight. The attacking midfielder has already racked up more goal contributions (five) in nine games this season than he managed in 33 games last campaign. The teenager's rapid rise has attracted some of the richest clubs in world football, and United are among those to have thrown their hat into the ring.

According to Argentinian news outlet , the Red Devils have 'taken the first step in negotiations' with senior figures at River Plate. And they have informed the South American giants that they would be willing to pay Mastantuono's , providing it's in instalments.

INEOS chief Sir Jim Ratcliffe has made it clear that he wants United to uncover the next big stars in the transfer market, rather than spend huge amounts on established names. Mastantuono fits the brief, having only recently made his senior breakthrough and never played in Europe.

But it is understood that the reply they got from the 17-year-old's camp was not positive. They have responded to every enquiry by telling clubs that Mastantuono is 'waiting for Real Madrid' and in 'no rush to leave River Plate'.

Real have also paid attention to Mastantuono's performances, but it is claimed that they would rather avoid paying the full value of his release clause. Marseille, Atletico Madrid and Paris Saint-Germain have also been gathering information on the Argentina Under-20 international.

Mastantuono was the centre of attention once again on Sunday, when he scored the first goal of the grudge match against Boca Juniors with an incredible looping free-kick.

Afterwards, River Plate boss Marcelo Gallardo said: "We have to support him. He's a player who inspires a lot of enthusiasm for his young age. He's a kid who has his feet on the ground.

"He has to feel like he needs to keep growing. He doesn't grow with the normality of any 17-year-old. If he does leave at some point, we'll have to analyse it. But that's not going to happen anytime soon."

Any teams hoping to get their hands on Mastantuono this summer were dealt a blow by River Plate vice president Stefano Di Carlo, who said that he will '' be staying for the rest of the calendar year.