The Real Madrid manager has been pleased with the performances of his goalkeeper so far this season and is not considering a change between the posts.
Los Blancos recorded a narrow 1-0 win over Granada on Monday thanks to a Karim Benzema goal in the first half, but the major talking point was again the decision to leave Casillas on the bench.
The Spain No. 1 was discarded by Jose Mourinho at Estadio Santiago Bernabeu last season and though many expected him to reclaim his starting berth under Ancelotti, the manager has instead opted to stick with Lopez -- a decision he is happy to stand by.
"Diego Lopez played the first game, he played the second. He's playing well, nothing more. The pressure is fuel to me (regarding the focus on the decision)," Ancelotti told reporters.
Monday's victory was the club's second in as many league outings, and Ancelotti reserved special praise for Benzema's goalscoring start to the season after grinding out the three points.
"Benzema is playing well and scoring. He has started well in the league," Ancelotti said. "The team was balanced. Luka Modric and Isco played well. Isco had to sacrifice a bit because he can attack more. The work of Di Maria was important."
Madrid's next match comes Friday when the club hosts Athletic Bilbao.