Real suffered a 2-0 loss in their Champions League tie on Wednesday, with Kylian Mbappe having a penalty saved.
Courtois said afterwards: "I think Liverpool is one of the teams in the best form at the moment. We competed well, we defended well. But offensively we struggled to create danger. We had good counterattacks, but we didn't finish well. It's difficult like that.
"In the second half they went 1-0 up and unfortunately we missed the penalty. And with the second one it was already very complicated."
Asked what is missing, the Belgian continued: "Maybe a bit of play. We did well in the second half. We are missing players, but that is no excuse. We lost against a better team and that's fine. Now we have to try to win at Atalanta and also on the two in January. To qualify and see what happens next."
On Eduardo Camavinga's injury, Courtois added: "It could be a tear. That's two or three weeks, minimum. We are the ones who are here. We have to keep fighting and competing. The youth team is doing well too, like Raúl (Asencio), who had a great game.
"There are more kids in Castilla and the Juvenil A who can help us."
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