Manchester United’s win over Liverpool at the weekend was tipped over the line by the team’s young stars. Amad and Alejandro Garnacho combined for the winner, with Kobbie Mainoo performing so well that he was subsequently called into the England squad, where he hopes to make his debut this week at 18. Well, also at the weekend, Manchester United’s academy teams shone, with a 5-2 win for the under-18s and 3-0 victory for the under-21s. And one of the players involved has managed to beat Kobbie Mainoo to making his international debut, last night making his bow at 17. James Scanlon makes interna…