'We can hurt them': Wigan boss Maloney eyes Man Utd upset in FA Cup
United have just two wins in their past nine matches in all competitions and have lost half - 14 - of all their matches so far this season.
Nine Premier League defeats in 20 fixtures is United's worst record since 1989/90, making Erik ten Hag's troubled team potential candidates for an FA Cup giant-killing.
They are eighth in the Premier League - 53 places above third-tier Wigan, who themselves have won just once in six outings.
Asked whether he thought United were vulnerable, Maloney said on Friday: "I think you see that in any team.
"We prepare the majority of the season against League One sides but in any team - whether they are in our division, the Championship or the Premier League - there will be areas defensively you can see you can try to take advantage of.
"There are always things that I think we have to try to hurt them or certain areas that we can hurt them. That's my job, I have to try to find them.
"I have to give my players the belief that we can do it. We have to create a match which is extremely difficult for Man United."
The DW Stadium is a sell-out for the first time since Wigan were last in the Premier League in 2013 - the year when Maloney was in the Latics side that shocked Manchester City in the FA Cup final.
Maloney is determined to put on a good show and even though his side are 17th in League One, he will not radically change their approach.
"When you play against a team two divisions above, you have to be aware of the talent they have so how we defend will have to be different to how we defend in League One," he said.
"But I still have to give the players belief and I'm not going to change how we play when we have the ball, just because we play someone so much different."