Former Manchester United midfielder Owen Hargreaves has tipped Amad Diallo to be a "special" player for the Red Devils in the future.

Diallo officially joined United from Atalanta BC in January and had been in impressive form for the club's Under-23s side before making his first-team debut against Real Sociedad in the Europa League on Thursday, featuring as a late substitute in the 4-0 win.

The 18-year-old could eventually cost Ole Gunnar Solskjaer's side in the region of £37m, and Hargreaves is excited by what the future could hold for the attacker.

"Well, I think when you sign players for that amount of money, you want them to have an impact. They obviously believe in him and that's why he was on the bench tonight (Thursday) and came on," Hargreaves told BT Sport.

'(Anthony) Martial and (Marcus) Rashford are setting the levels of what it means, but for the money they paid, they're going to want a pretty significant impact. For Jadon Sancho, that category of player is already established, but Diallo is at the start. Hopefully he's a special one for the future."

Diallo could make his full debut for United in the second leg of the last-32 tie at Old Trafford on February 25.