Encouragingly, Rafael and Darron Gibson also both played 90 minutes on their comeback from shoulder and foot injuries respectively.
With Warren Joyce confirming beforehand he is staying in charge of the side despite being targeted for the Hull City job, the Reds knocked the ball around with confidence but the opening quarter of an hour was devoid of any real opportunities. That all changed when Morrison collected the ball on the edge of the area, worked it onto his right foot and curled a top-class finish past Lee Nicholls.
Morrison was then inches away from connecting with Rafael's excellent cross and was almost through again, only to be ushered away by the stout Rob Kiernan. Paul Pogba nearly doubled the lead with a well-placed free-kick that was flipped away brilliantly by Nicholls six minutes before the break. Rafael, meanwhile, continued to impress and another teasing centre was agonisingly out of Will Keane's reach in the middle. However, Wigan finished the half on top and carved out their clearest opening when Danny Redmond's cross was almost met by Nouha Dicko - a similar chance to the one at the other end moments earlier.
Jesse Lingard was heavily involved at the start of the second half and forced a save out of Nicholls with a stinging drive when Pogba flicked the ball invitingly into his path before slamming a right-foot shot wide following a storming run forward by Michael Keane.
Morrison doubled his - and United's - tally with a beautiful finish after 54 minutes, finding the bottom corner of the net with an instant shot