"Iker is possibly the best goalkeeper in the world," the German tactician was quotes saying on the club's website.
"We knew that the game would be decided in the details and today the best were the forwards and Casillas."
Real Madrid didn't produce a vintage display but they were efficient. Casillas made some heroic saves and the strikers capitalized on their chances to snatch three valuable points.
"What's best was watching the players suffer to grab the victory. Some times you have to play hard and fight because you can't produce a beautiful display."
"We also knew that Zaragoza's position in the league was not an indication of how strong they are as they are among the best five or six teams in Spain," concluded Schuster.
The Merengues are seven points clear on top of the Primera Liga, 44 points, while Zaragoza are 10th with only 21 points.