After victory at Getafe, Vini Jr was accused of getting Allan Nyom sent off and also firing taunts at coach Jose Bordalas.
Courtois said afterwards: "It's not easy. At 18, many of you have made fun of him. He didn't do anything wrong, he came on and they're against him. It's normal that he has responses.
"They looked for him from the start and he unhinged the opponent. He had a good response. His entry made us create more danger. They look for him. It's very unfair to him. He's a great kid who has to keep doing what he does. He's had a great start to the season and I expect more of that tomorrow and Sunday."
The Belgian also said: "It's not always easy for a stadium to look out for you. For players to hit you hard. He's been improving. If he's learned to live with conflict and unhinge opponents... Diego Costa drove Premier League defenders crazy because he did that. If Vini can do it, it's perfect for us. The important thing is that he stays focused and plays his game. He's one of the best in the world."