It will be United's first game since Amad Diallo and Bryan Mbeumo's departure for AFCON.
"We need to play a little bit different," Amorim told MUTV. "We lost some one-against-one. We will see but we'll be ready for the game.
"It's perfect, it's not perfect as we don't have all the players, but we are ready. We have players that can solve the game for us, so are happy with that.
"Yes (we have lost Amad and Mbeumo) and also Nous (Mazraoui)," Ruben continued. "So Nous is also really important for us but, when one player is out, we have opportunities for other players.
"Last year, in some games, we managed to win, especially in Europe, without Amad. Bryan was not here, so we already have those moments of difficulty. So we are ready, more than ready, to cope with that."
On Benjamin Sesko's return to fitness, Amorim was bullish.
"I think he is a different type of striker," said Amorim. "The only one in that part because Josh (Zirkzee) is more like a no.9 and 10 at the same time, a little bit like Cunha. Ben is a guy who likes to be in the box. He makes a lot of runs.
"Of course, if you look at him, you can feel that he has so much more to give. He is improving the physicality, he was one month without playing, but he is ready and he is going to help us."