Manager Santiago Solari offered several 'homegrown' players a chance in the form of Federico Valverde, Marcos Llorente, Jesus Vallejo and Javier Sanchez as CSKA completed the double over Real - despite finishing last in the group.
To say they didn't impress would be an understatement and Carvajal was particularly vocal after the 3-0 defeat.
"Three weeks ago there was talk that the homegrown players could play," he told Movistar+.
"But it turns out that they might not worthy of the first team."
Carvajal also touched on the home supporters jeering playmaker Isco after he missed a clear-cut opportunity for the Group G winners.
"I have not seen if he was whistled by the fans or not, but the only thing I can say about Isco is that he has been here for many years and he is a brave player.
"When things are not going well, he asks for the ball and tries to change the game rather than disappear."