The hosts pressed for an equaliser but it was United who looked more likely to score again as substitute James Wilson and Barmby were denied in quick succession by Rudy. The Reds survived a stoppage time scare after Iqbal Hussain was bundled over by Patrick McNair just outside the penalty area, but Safirul Sulaiman fired his free-kick high over the bar.
United had done enough to claim a deserved victory and with it third place in the NexLions Cup.
United: Gollini; Love, Dalley, Grimshaw, Rowley (Evans 61), Pearson (McNair 84), Weir, Rothwell (Daehli 34), Barmby, Gorre (Rudge 61), Byrne (Wilson 61).
Subs not used: Sutherland (GK), Ioannou