Ethan Wheatley put United ahead after 19 minutes, with his effort from the edge of the area striking against both posts before crossing the line.
Gabriele Biancheri then made it two just before the hour mark, Ashton Missin's cross from the left was parried into the feet of the forward who doubled United's advantage.
Biancheri was at it again to double his own individual tally just five minutes later, with Missin's shot again falling kindly the way of the Welsh-born attacker, as he tapped home to make it 3-0.
