Warren Joyce's youthful side were not at their best throughout and were a little fortunate to take a lead into the break. There was a let-off when Connor Loftus beat Ben Amos to an Andy Haworth cross to hit a post when the Reds were down to 10 men with Jesse Lingard getting treatment.
Lingard was unable to continue after a nasty-looking challenge and his replacement, Tyler Blackett, opened the scoring on 41 minutes after Amos was worked by Luke McCarthy and Patrick Cregg. Some neat skill by Larnell Cole won a free-kick that he flighted into the box. Ritchie Branagan could only paw it away to Blackett, who looped a slightly unorthodox volley straight into the top corner of the net.
Michael Keane doubled the lead when a short corner led to Luke Giverin crossing dangerously and the defender stole in purposefully to fire past Branagan. John Cofie spurned a couple of good openings, after also dragging a shot wide in the first half, as United struggled to kill off their spirited opponents with a third goal.
Joyce's son Wade, who was on United's books, came on as a substitute for the visitors and there was another change for the Reds when Cofie landed awkwardly and was replaced by Alberto Massacci with nine minutes left. The young Italian, finding himself in an unfamiliar forward position, had a couple of half-chances but it stayed at 2-0.
United: Amos; M.Keane, Thorpe, Fryers, McGinty; Vermijl, Lingard (Blackett 12), Cole, Giverin; Cofie (Massacci 81), W.Keane. Unused subs: Lawrence, Leao, Jacob.