Rothwell then hammering off target with his final touch before being replaced by Andreas Pereira.
Larnell Cole cut inside, only to fire wide at the near post, and there was no real late rally by the Reds, despite four minutes of injury time, with the visitors pretty comfortable in defence to clinch an eighth successive win at Under-21 level.
Joyce's youngsters are in action again next Monday at Leicester City's King Power Stadium, with the game again live on MUTV and there is a need to get three points on the board if the team is to start climbing the table.
United: Johnstone; Love (Janko 62), Thorpe, Ekangamene, Blackett; Cole, Petrucci (Pearson 78), Rothwell (A.Pereira 75), James; Lingard; W.Keane. Subs not used: Gollini, Varela.