The Belgian Red Devils missed out on a spot in the UEFA Nations League after throwing away a two-goal lead against France on Thursday night.
Courtois says he is preparing for Sunday's clash as if it were a friendly encounter.
"Saturday's match against Italy is pointless," Courtois told reporters, as per Goal.
"Being third in the Nations League is pointless. I don't know why we have to play that match. I'll take it as a friendly match."
The number one ranked side in the world will be without star striker Romelu Lukaku on Sunday afternoon.
"It's an overload. He didn't feel 100 per cent to play tomorrow. It's soreness in his tissue," Martinez said.
"Every decision taken involves both medical departments together for the good of the player."