Ruben Amorim's men took the lead after 24 minutes when Matheus Cunha netted his first United goal, followed up 10 minutes later by a deflected Casemiro effort to double our advantage.
Bryan Mbeumo extended our lead to three on the other side of the break, but former United man Danny Welbeck threatened to pull the visitors back into it when he clawed one back, direct from a free-kick.
Charalampos Kostoulas reduced our lead to one in stoppage time, but Mbeumo put the result beyond doubt even deeper into added time, putting another three points on the Premier League board for United and, temporarily at least, moving us into fourth in the table.