The home side had the better of the early possession and edged their noses in front in the 18th minute after their opponents failed to deal with Ronaldo's low cross, allowing Karim Benzema to tap home.
It was 2-0 less than 10 minutes later courtesy of a brilliant solo strike from Ronaldo, the Portuguese international swerving two defenders before thumping the ball past Beto into the bottom corner.
The second half started with a bang. A catastrophic error from Federico Fazio gifted the ball to Ronaldo inside the box and the forward made no mistake from close range.
The former Manchester United ace completed his hat-trick just before the hour mark, tapping in Gonzalo Higuain's pin-point cross to hammer another nail in Sevilla's coffin.
It didn't all go Madrid's way. Higuain was red-carded in the 66th minute for a foul on Coke Andujar, having picked up a caution for a handball earlier in the game.
The visitors did pull one back through Manu del Moral with two minutes left on the clock, but it proved to be little consolation for the travelling supporters.