Moyes succeeded Alex Ferguson on July 1 following the legendary Scot's shock retirement and the 50-year-old has endured a challenging start to his Old Trafford tenure.
His chief transfer target, Barcelona midfielder Cesc Fàbregas, has spurned United's advances, while unsettled striker Wayne Rooney has been the subject of two unsuccessful bids from Chelsea.
The former Everton manager has also seen his side win just two of seven pre-season games, but the English champions will start as strong favourites against a Wigan team who slipped into the Championship after stunning Manchester City in May's FA Cup final.
Victory over Wigan would give United the first piece of silverware of the new season, but Moyes says the credit for a positive outcome beneath the Wembley arch would have to go to his illustrious predecessor.
"I will be trying to make this the first trophy of many. But, if we win, it's really something that will have been earned by Sir Alex," he told Inside United magazine.
"It's because of his good work in the Premier League last season that we're in the Community Shield.
"I'll do my best to finish off the job but it's Sir Alex who will deserve a lot of the credit if we're successful at Wembley."
United have sold over 47 000 tickets for the traditional curtain-raiser to the English season a record for one club at the new Wembley, which opened in 2007.
The fans travelling to west London will be eager to discover how Moyes intends to set up his side for the new campaign, after he experimented with different line-ups during the tours of Asia and Sweden.
Rooney has reportedly declared himself fit after missing United's entire pre-season programme with hamstring and shoulder injuries, handing Moyes a selection dilemma.
Whether Rooney plays or not, Moyes needs his players to hit the ground running, with games against Chelsea, Liverpool and Manchester City arriving in close succession after their Premier League opener at Swansea City on August 17.
Whereas United have made just one close-season signing to date, acquiring 20-year-old Uruguayan right-back Guillermo Varela from Penarol, Wigan have already attracted 10 new players to the DW Stadium.
Irish international winger James McClean arrived from Sunderland on Thursday, joining Grant Holt, James Perch and Scott Carson as players who have joined the club since Owen Coyle became coach.
Despite the upheaval at Old Trafford caused by Ferguson's departure, Coyle believes the 20-time English champions have found an ideal replacement.
"Sir Alex was there for a long time, particularly for football," said Coyle, who succeeded Roberto Martinez after the Spaniard moved to Everton to fill the vacancy left by Moyes.
"The way football works, that time is probably worth 10 times that amount in any other walk of life. Will it be strange? Maybe to begin with. That is only natural.
"But when you see the stature of the man who is there, you know he is the right custodian for Manchester United."
Wigan have won one and lost 16 of their 17 previous encounters with United, but they opened their Championship campaign strongly last weekend, winning 4-0 at Barnsley to take an early lead in the English second tier.
Coyle must do without club captain Gary Caldwell, who is recovering from a hip operation, while fellow centre-back Ivan Ramis is side-lined with a knee ligament injury.
Irrespective of the result, history will be made on Sunday as the game will represent the first time an official match has been played in England with goal-line technology in place.
The Hawk-Eye system, which has also been installed at every Premier League ground, uses 14 high-speed cameras to monitor the two goals and sends a signal to the referee within a second of the ball crossing the goal-line.- SAPA-AFP