Italian youth international Macheda is the U18s' top scorer this term with eight goals, including his strike in the 2-1 third round victory over Brighton & Hove Albion. Welbeck, an England U17 international, has scored seven goals this term. Together, they form a formidable partnership up.
"They are both very good players," United coach Paul McGuinness told PA Sport. "Danny is still only young and has another year at this level. He's a very talented player and all the other players respond to that.
"Federico is a very good technical player. He's a good finisher, makes good decisions and some very clever runs. In some ways he has a style like Dimitar Berbatov. His touch is very good."
Rome-born Macheda has made a strong impression on and off the pitch since arriving in the summer from Italy, where he was on Lazio's books. "His English is coming on, he's a bright boy," added McGuinness. "He understands what we're after and he has fitted in well with the culture of the club."
"Federico and Danny are on a really good wavelength. That is what you want, good partnerships. When you see them in training and you look at the likes of Rooney and Tevez and the way they link up, those two lads are capable of doing similar sorts of combinations."