Barcelona goalkeeper has urged his teammates to finish up the encounter after securing a 1-0 from the first leg of their quarter-final.
German international ter Stegen feels the Red Devils will be out for revenge and wary of a famous fightback like the one at Paris Saint Germain in the previous round.
So he has urged Barca to be ruthless and finish off the job in hand.
The goalkeeper told the Daily Star: “We are facing a team who is eager.
“They have had some games away which they won, and of course the advantage is not so big for us.
“We want to defend it and uphold it – but we want to state our superiority and for that, we need to play a good game.
“They are very quick. You always have to have be alert.
“I think it’s the key to winning this very difficult game. They know how to play in a very calm way. They made things really hard for us in the first tie.
“So we want to go out and master the game, have the ball as much as possible.”
Ter Stegen wants no repeat of Barca’s shock collapse to Roma at this stage of the competition last season.
Barca won the home leg 4-1 but lost the return game in the Italian capital 3-0 to crash out on away goals.
Ter Stegen added: “We don’t want that to happen again. We need to bear it in mind and look forward and this is a good time to achieve a good success for us, with all our fans around us, so hopefully, we will beat them.”