Manchester Utd 4 Wigan Athletic 0

Latics made by far the brighter start, and could have been ahead inside 10 minutes but for a superb save from Sergio Romero to deny on-loan right-back Callum Connolly.

Then, five minutes before half, Michael Jacobs could only swing his foot at thin air from the penalty spot with the goal at his mercy.

And Latics were made to pay a high price as United took the lead four minutes later, with Marouane Fellaini heading home from close range.

The visitors also started the second half in determined mood, but David Perkins - without a goal in over four years - was unable to take advantage of their best chance.

Despite goalkeeper Romero being on the ground and out of the equation, Perkins saw his low shot from the edge of the area blocked by Chris Smalling.

And United produced a harsh lesson in ruthless finishing to give the scoreline a lop-sided look.

Smalling notched number two himself with a clinical header from Anthony Martial’s cross just before the hour mark, before the Frenchman supplied number three for Henrikh Mikhitaryan with 16 minutes to go.

With Latics out on their feet after an admirable effort, United added a fourth with 10 minutes to go, Bastian Schweinsteiger volleying home from close range from Wayne Rooney’s corner.

It wasn’t the result the 3,000 travelling supporters were looking for, but they certainly made the most of their big day - singing loud and proud from the first minute until the last.

And if their side had made their most of their first-half dominance, the result could well have gone the other way.

Latics were quickly into their stride, with Sam Morsy getting stuck in to Fellaini and the rest of the United midfielders from the word go.

The visitors created the first chance of the game, and had Connolly not struck his rocket from 25 yards so perfectly - straight at Romero like an Exocet missile - the goalkeeper might have been struggling to keep it out.

Juan Mata sent United first sight at goal flying harmlessly over the bar from 15 yards, and Latics were almost the architects of their own downfall moments later.

Morsy lost the ball on the edge of the United box, allowing the hosts to break, and it needed a timely interception from Dan Burn to stop Mkhitaryan in his tracks.

Again United looked at their most dangerous when a Latics move broke down, this time Mata trying to find Mkhitaryan unmarked at the far post, and Connolly working wonders to divert the ball to safety.

Latics created and squandered a massive chance five minutes before the break, when Jacobs had a clear sight of goal from the penalty spot, only to completely fluff his lines.

And there was an air of inevitability when, just four minutes later, it was United who secured an interval advantage, with Schweinsteiger crossing for Fellaini to get over Connolly - a complete mismatch at the far post - and nod home with aplomb.

United picked up where they’d left off after the restart, with a mistake from Burn - a rarity in recent weeks - allowing Tim Fosu-Mensah to advance into the box, only for the right-back to pull his shot wide of the near post.

Schweinsteiger almost walked his way through the heart of the Latics defence on 51 minutes, before Jake Buxton flew across and deflected the ball behind for a corner.

Latics then wasted another golden chance to score, when Jacobs’ cross was pushed out by Romero to Perkins, whose shot at goal lacked any real conviction - not surprising given his goalscoring record - allowing Smalling to block.

And the England centre-back rubbed salt into the wounds by popping up at the other end on 57 minutes to double the lead, heading home Martial’s cross after getting the run on Stephen Warnock at the far post.

Wigan’s response was to throw on Yanic Wildschut for Perkins - a change they’d been preparing before the second goal - with former United junior Ryan Tunnicliffe soon joining the fray in place of Will Grigg.

Tunnicliffe almost announced himself on to the scene in dramatic fashion, heading straight at Romero within seconds of coming on.

But United secured their passage into round five with number three on 74 minutes, Martial’s cross finding Mkhitaryan, who beat Jakob Haugaard from close range.

Latics threw on new-boy Marcus Browne for Shaun MacDonald, and the on-loan West Ham man almost scored with his first touch, only for Smalling to again get in a timely block with Romero struggling.

United weren’t finished, though, and Schweinsteiger made it four with a clever overhead kick from Rooney’s corner, which produced the biggest cheer of the day from the home fans.