The Dons will be looking to take revenge on Steven Gerrard’s side after their 4-2 league win at Pittodrie last month.
The game was marred after Morelos – who scored twice – and Scott McKenna were sent packing after an ugly clash.
Dons boss Derek McInnes said: “Rangers have got very good players, a very strong squad that Steven has put together. But, for me, Morelos is the star.
“He’s the one who even when Rangers are not at their level can produce and be the difference.
“It would be wrong for us to focus on a particular player, but I think it was a wee reminder for us recently.
“We have to get tight and make sure we try and limit Morelos’ influence in the game.”
“There’s an obligation from everyone in my team – not just singling out Scott – to play the game in the right manner, a competitive and aggressive manner that is needed to win the game,” said McInnes.
“It’s always more difficult when you lose players or are booked early on. The responsibility is on everyone.
“There were a lot of positives despite the result from last time. In any big game, major incidents can have a bearing – if it’s referee decisions, a sendingoff, indiscipline.
“It’s important for us to accept the responsibility that if we want to be a cup-winning team then we need to beat good teams.
“The task of beating a very good team like Rangers is a lot more difficult if you don’t bring a level of performance and a level of discipline.”
The Dons have been solid on the road but found it harder to win at home in recent weeks.
McInnes is aware that defeat today is likely to end the trophy hopes of the team who bows out, with Celtic on course for another league title.
“It will be two teams with the intention of not only getting into the semi-final but winning the cup, so it’s got the makings of a very good tie,” added McInnes.
“We put pressure on ourselves to be as competitive as we can in the league and to win a cup.
“That’s our intention at the start – we feel we’re one of the few teams that really believes at the outset that we are going to win it.”