The England centre-forward won United a fourth-minute penalty, missed by Javier Hernandez, as he went down under a 'challenge' from the Wigan goalkeeper Ali Al-Habsi.
A goal for Paul Scholes, on his 700th appearance for the club, and one each for Alexander Buttner and Nick Powell - each making their first - ensured a comfortable afternoon for Manchester United although the actions of Danny Welbeck were less admirable.
The England centre-forward won United a fourth-minute penalty, missed by Javier Hernandez, as he went down under a "challenge" from the Wigan goalkeeper Ali Al-Habsi.
Further, according to an angry Wigan manager Roberto Martinez, Welbeck should also have been dismissed by referee Michael Oliver late in the game, for a high, sliding tackle which earned him a yellow card, not the red that the visiting dugout felt appropriate.
In all, Martinez, usually unflappable and reasonable in examining his team's performances, was furious at the performance of the official.
"He dived, he dived for the penalty, you will see that," said Martinez of Welbeck and the early spot kick decision. "And the last challenge by him on Franco [di Santo] was completely reckless. Under the new regulations, you can't do that. The foot was over the ball, it was reckless, dangerous.
"That is a red card, for Wigan Athletic, for Manchester United, for anyone. The referee should give that for both teams.
"I thought today, for whatever reason, the referee was not going to measure the two teams in the same manner. I'm not blaming the referee for the scoreline but I'm looking for a little bit of fair ground on which to perform.
"I have had three sendings-off in my last two games here. For whatever reason, we don't seem to be measured in the same manner as the team at home. Today's penalty was as bad a decision as you are going to see.
"I was angry at the penalty. You need to be involved in football and you know what he's trying to do. I'm sure, if you see the replay you will understand what I'm trying to say. It was a shocking decision."
Those replays indeed showed there had been no contact between the players and Wigan's animated protests at Oliver's decision looked fully justified before Al-Habsi saw that justice was done by diving low to the foot of his left-hand post to keep out Hernandez's shot.
The save eventually proved to have merely delayed the inevitable with United turning in an attacking performance all the more impressive for the absence of Robin van Persie and Shinjo Kagawa, both rested ahead of the start of United's Champions League campaign in midweek.
It took until the 51st minute for Scholes to turn United's possession and openings into a goal as Nani's low cross into the six-yard area presented Al-Habsi with a major problem, the goalkeeper merely diverting the ball into the path of Scholes who converted into an open goal.
Dutch full-back Buttner had already made his mark on proceedings, his marauding runs and uncompromising tackling making him an instant favourite with the home supporters.
That cult status was further cemented after 63 minutes when Welbeck dispossessed Ivan Ramis in the Wigan area, feeding the ball to Giggs who, in turn, found Buttner for a fearsome shot which was steered in by Hernandez.
Buttner looked keen to claim that goal but only had to wait three minutes before scoring one that was undoubtedly his. This time it was a memorable solo effort as he slalomed his way into the area, shrugging off three challenges and scoring, via Al-Habsi's leg, from a tight angle.
The one-way traffic continued, Van Persie appearing as a substitute and also on the end of a Hernandez cross, somehow failed to turn it into an open goal.
Eventually, it was left to Powell to prove why Sir Alex Ferguson would say of him after the game that "he's going to be a real player." James McCarthy played the ball out of defence, directly to Rafael who squared for the onrushing Powell to gather the ball and steer a superb shot into the far corner of Al-Habsi's goal.
Wigan are not the first, and will not be the last, vanquished visitor to complain of refereeing injustices and, ultimately, even Martinez was happy to concede that the far superior team won. For United and Ferguson, the significance of the result also lies in the goal difference, where a modest-looking "plus one" has suddenly become a "plus five."
"I was pleased with the way we went on and scored goals," said Ferguson. "Last year we lost the league on goal difference and I said that wouldn't happen again."
Man United (4-4-2): Lindegaard; Rafael, Ferdinand, Vidic (Evans 76), Buttner; Nani, Carrick, Scholes (van Persie 71), Giggs (Powell; 71); Hernandez, Welbeck. Subs de Gea, Valencia, Cleverley, Kagawa.
Booked Buttner, Welbeck
Wigan (3-4-3): Al-Habsi; Ramis, Caldwell, Figueroa; Boyce, McCarthy, McArthur, Beausejour (Jones 68); Di Santo, Maloney (Gomez 58), Kone.
Subs Crusat, Watson, Pollitt, Boselli, Miyaichi.
Booked Boyce, McArthur.
Referee: M Oliver
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