After defying all the odds by beating Premier League leaders Chelsea in the previous round, City will be up against it again when they face Gus Poyet's Sunderland for a place in the quarter-finals at a packed Coral Windows Stadium.
Boasting a squad containing experienced internationals such as Jermain Defore, John O'Shea, Sebastian Larsson and Adam Johnson, Sunderland will be expected by many to secure their spot in the last eight of the competition.
Despite City not being the favourites for the tie, however, Morais says that the Bradford squad is in a good place at the moment and he knows anything is possible when the magic of the F.A Cup is around.
Morais said: "I think we have to adopt the same attitude we did for the Chelsea game, and that is to stay nice and calm.
"We are playing a Premier League team - we have absolutely nothing to lose.
"We have a lot of players here who are currently in a good vein of form and who are in a good period in their careers.
"We go into this game with confidence. All we can do is our very best for ourselves, our families, the supporters and the club.
"It is the F.A Cup - anything can happen.
"We will certainly have confidence and belief going into the match. From there on, we'll just give it our best shot."
Following City's amazing victory over Chelsea at Stamford Bridge last month, the events of this Sunday at Valley Parade are likely to catch the attention of many football supporters around the country.
As the Bantams look to shock the nation once again with another giant-killing, Morais feels the club's stunning win over Jose Mourinho's men can't help but give the players belief that they can pull off a further upset.
Morais added: "We felt it before the Chelsea match and we feel it now - it is the F.A Cup and anything can happen.
"The Chelsea win obviously gives us confidence going into this match. With this game being at home as well this time around, it will be even greater for the fans.
"To win the match would be unbelievable but we are playing a Premier League team and we have it all to do.
"All we can do is keep doing what we are doing. There is a good feeling around the camp at the moment - we love running and working hard for each other.
"When you do that, you can give any team a difficult time."