The reigning European champions needed a late penalty from Gareth Bale to secure a vital three points in a tense game in Andalusia that saw Cristiano Ronaldo sent off for aiming a kick at Cordoba defender Edimar.
And Casillas, who was reinstalled as Madrid's outright No.1 at the start of the season, believes their showing proved they are ready to end a three-year wait for the Spanish title.
“Perhaps it wasn't our best performance of the season but we took all three points," the Blancos captain told reporters. "The pitch was very tough to play on, it was very dry.
“We like to pass the ball around, with lots of movement; we were made to work today but we got the win.
“No one was at their best in this game and we got through this more with character than with good play. These are the types of games that win league titles and we had no choice but to win.”
It was Real Madrid’s third straight victory in La Liga following defeat to Valencia earlier this month, although this month has seen their Copa del Rey hops crumble as they were knocked out by Atletico.
The victory leaves Carlo Ancelotti’s side one point clear at the top of the Liga table with a game in hand over second-placed Barcelona.
