The Belgian goalkeeper says that he will be an Atletico Madrid fan for both games against his permanent employers and believes that they can reach the Champions League final
Diego Simeone's men host the Blues in the first leg of their last-four tie on Tuesday, aiming to reach the final of the competition for the first time since 1974, and the tie sees the on-loan Belgian up against his permanent employers for his second time since being sent to Spain three years ago.
On the first occasion, Atletico beat the Londoners 4-1 in the 2012 Super Cup, a result that Courtois is hopeful of replicating this time around.
"For me, the fact that we've drawn Chelsea, like we did in the European Super Cup, is special because, even though I'm at Atleti, Chelsea are my club too," Courtois told Fifa's official website.
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"I want to win trophies here and I'll be an Atleti supporter for these two games but, at all other times, I'm a Chelsea fan too. I hope they win the Premier League, just not these two [Champions League] matches.
"I really hope we can reach the final as we're so close. [Chelsea] are the favourites but Barcelona [in Atleti's quarter-final] were too."
Atletico lead La Liga by four points from Barca and are on course to claim a double that few would have anticipated at the start of the season and Courtois feels that coach Simeone deserves much of the credit for their achievements.
"So much of this success is down to Simeone because he's the man who’s guided us this far," the 21-year-old added. "From the first time he spoke to us when he was appointed, he told us he had a very clear idea about how he wanted things to be done and how he wanted us to play.
"That clarity has been key. You might be out for five weeks but, when you come back, you know exactly what you have to do because the way we set ourselves out doesn't change. We know what each player's role is."