The Argentina international broke Gerd Muller's record of scoring 85 goals during one calendar year with his double against Real Betis on December 9, and then increased his tally for the year to 88 goals with two in the Copa del Rey clash against Cordoba.
But going into the match against the Blaugrana, the Belgium international said that he is not afraid of facing the South American star.
"Do I fear Messi? No, no, I am not afraid of anyone," the 20-year-old told reporters.
"He is a great player and we respect him very much, but there is no fear.
|7/5||Lionel Messi is 7/5 with Bet365 to score two or more against Atletico Madrid on Sunday
“Now we are focused and the team wants to do their best at the Camp Nou. Barcelona have a very good group of players."
Courtois also added that Atletico's 3-0 cup victory over Getafe on Wednesday proved his side's hunger for success in the competition.
"The cup is very important. I have told several of my teammates of the importance of playing in the cup final for this club," he said.
"It would be spectacular, playing in a big stadium which can sometimes be 40,000 for each game. We can reach the final.
"It will be difficult. It won’t be great to face either Barcelona or Real Madrid, but we must advance first in order to do so."
Atletico travel to Camp Nou to face Tito Vilanova's men on Sunday, December 16 at 21.00CET.