Real defeated Juve 1-0 in Tuesday's Club World Cup round of 16 tie.
Courtois said afterwards: "The defensive commitment from the whole team was outstanding. That's what counts, we did a great job. It's always better when you don't concede.
"It depends on the moment of the game and the movements of the opposition. If everyone runs like they did today or like they did against Salzburg, it's very difficult for teams to score goals against us.
"I think we had a lot of chances in the second half, but their goalkeeper was really good. Luckily, we managed to score and I think we defended well."
Trent is improving us
Gonzalo Garcia's winner was created by Trent Alexander-Arnold and Courtois said of the former Liverpool fullback: “He could have provided several assists already in the tournament.
"His previous assist against Pachuca was excellent. In training, his striking is unbelievable, his free-kicks and corners are on another level. I don't think I've seen anyone with his quality in striking and crossing.
"As a goalkeeper, he's a nightmare at times. He keeps you on your toes and forces you to work hard to make stops. He makes us improve."