Los Blancos overcame Malaga 1-0 with a Cristiano Ronaldo goal on Saturday to maintain a three-point lead at the top of La Liga and Lopez has been ever-present in the domestic campaign, appearing in all 28 league fixtures.
Casillas recently hailed his counterpart, noting that los Merengues are where they are in large part due to Lopez's displays, and the 31-year-old spoke of his happiness at Santiago Bernabeu.
"I am privileged to play for my team," the 32-year-old told journalists after the Malaga game. "I strive to play every game and what we are all doing is all seeking unity."Iker is the captain and a team emblem. His words are appreciated and I have always had enormous respect for him. We both have good qualities and compete for a spot on the best team in the world."
Victory over Malaga allowed los Blancos to retain their position at the top of the table but Lopez stressed that his side must now focus on next Saturday's Clasico, in which the club hosts reigning champion Barcelona.
"[The Malaga game] pushed us close and was complicated," the Spanish stopper continued. "But in defense have been at a high level. Leagues are won in games like this.
"The Clasico will be a very important game. We know its importance and we wait until Sunday. It's a good opportunity and we have to defend our advantage and go game by game."
Madrid has 70 points from 28 games this season, leading second-placed Atletico by three points.