Dimitar Berbatov scored a hat-trick as Manchester United thrashed 10-man Wigan to move level on points with Premier League leaders Manchester City.
Park Ji-sung coolly slotted the hosts into an early lead before Wigan striker Conor Sammon was harshly sent off for catching Michael Carrick in the face.
Berbatov fired United 2-0 ahead and netted the third after the break with a neat turn and powerful finish.
Antonio Valencia rifled into the corner before Berbatov scored from the spot.
Wigan were enraged by referee Phil Dowd's decision to award the penalty for an Antolin Alcaraz challenge on Park which took place just outside the box.
But the scoreline did not flatter United, who have now hit 16 goals in four successive league victories to reignite their title challenge.
City's 0-0 draw at West Brom means both teams have 45 points, with City's lead on goal difference now cut to only five.
And United's victory was all the more impressive given the makeshift nature of a team depleted by illness and injuries.
Michael Carrick and Antonio Valencia lined up in defence, Darron Gibson in midfield and Berbatov was handed a rare opportunity alongside Javier Hernandez up front.
Wigan have now lost all 14 of their matches against Manchester United
For their part, Wigan came into the game off the back of impressive draws with Chelsea and Liverpool but, after conceding an early goal, their chances of getting anything out of the game were effectively ended by the dismissal of Sammon.
The striker's flailing arm caught Carrick in the face, but there appeared to be little aggressive intent in the incident.
The red card ended any chance of a contest, but in truth United had shown plenty of menace even before Park's early strike.
The goal was brilliantly created by Patrice Evra on the left, who skipped past two Wigan players and cut the ball back for Park to side-foot precisely into the net.
It was 15 minutes before Wigan enjoyed any sort of sustained possession, but when they did it prompted a great chance for Sammon.
Ronnie Stam's cross from the right was inviting for the lone striker but he inexplicably failed to get any sort of header on the ball.
United were soon back on the offensive with a Nani cross sparking mayhem in the Wigan box and Gibson, Ryan Giggs and Berbatov trying their luck from long range.
Stam remained Wigan's brightest spark, getting in behind Evra on the right and delivering a succession of crosses which Wigan's forwards were unable to make the most of.
The momentum swung back United's way as Sammon's controversial red card was swiftly followed by Berbatov's second goal in as many games.
A Gibson cross was flicked on by Hernandez to the Bulgarian, who held off Alcaraz and lashed home with his left foot.
United almost extended their advantage at the start of the second half, but Park's free header was directed straight at Wigan keeper Ali Al Habsi.
Hernandez then had a penalty appeal turned down despite being wrestled to the ground by Maynor Figueroa.
United have won their last eight Boxing Day matches
United's sense of grievance was short-lived as Berbatov collected a pass from Valencia and fired past Al Habsi.
Valencia then made it 4-0 with a rasping drive across Al Habsi after a corner was cleared straight to Carrick.
Then came the penalty incident which presented Berbatov with the chance for his hat-trick, an invitation the Bulgarian gratefully accepted by passing the ball into the corner of the net.
Wigan never gave up but could not create a clear opportunity as United keeper Anders Lindegaard maintained his 100% Premier League clean sheet record.
Wigan boss Roberto Martinez: "The red card is a shocking decision. There was a little bit of a fight, as there was every time the two players went for the ball. None of them should have been a red card. None of them were malicious. There was no intent.
"If you want to show a red card using those standards, do it, then you will end up with six men each.
"Anyone who has been on a football pitch knows that incident was a normal action.
"I was surprised when he gave the free-kick. To see the red card, I was gobsmacked."
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