Slot says he needs to adjust given Vinicius Junior's absence on Wednesday due to injury.
He said on Tuesday: "Yes, definitely. We approached it differently because a new player is going to play for them with different qualities. We knew when Vinicius would’ve started, I had to prepare them for him and (Kylian) Mbappe and all the others.
"But they are probably the main attacking threat for them. Now, with him not playing, we have to expect something else. I think he played almost every game for Madrid so it’s again quite difficult for us now to understand what we can expect. But what we do know what we can expect is 11 players with great quality and we try to prepare them in the best possible way.
"Will (Jude) Bellingham play as a 10? Will he play from the left? Will he play from the right? Will Endrick come in? Will (Arda) Guler start? They have so many options, which now is a bit more difficult for us to see what they’re going to do. If Vinicius would’ve been fit I think I’ve come up with their line-up, but now it is going to be a bit of a surprise for us maybe.
"But the thing we do know is that we play 11 great players in a very good team."
On facing Kylian Mbappe, Slot also said: "A lot of questions about the team we face and my opinion about them. The only thing I can tell you is I’m not bothered about what is his best position. The only thing I am bothered about is his quality. We have to face that quality and we have to play him in the best way.
"He has shown so many times that he is so difficult to defend for his country and for Paris Saint-Germain and also for Real Madrid. If Vinicius would’ve played it would’ve been one of the best players that football has at the moment. So, now it’s Mbappe, who is still there.
"I’m not the manager of Madrid so it’s not up to me what his best position is or not. I think every position he plays, he’s one of the best players in the world. We have to be ready for him."
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