The 21-year-old signed for the Blues in 2011, but was immediately sent on loan to Atletico Madrid, where he is now in his third season.
As Courtois has emerged as one of the best keepers in La Liga, speculation over his future has ensued and even Barcelona president Sandro Rosell revealed his admiration for him earlier this month.
Courtois maintains that he is happy at Atletico, where he feels he has become one of the top five goalkeepers in the world.
"I am in my best form and I feel that I am among the five best goalkeepers in the world," he is quoted by AS.
"I've grown a lot at Atletico, especially last season when we won the European Super Cup and the Copa del Rey.
"I've made great progress, especially in terms of speed, reflexes and experience. "
On his future, Courtois did not want to speculate about what would happen.
"I want to play, I will not be sitting on the bench. At Atletico I feel great and it allows me to play in the Champions League," he added.