Ronaldo had taken his tally of European goals to 100 in the quarter-final win over Bayern Munich, which included a second-leg treble, and was once more the man for the big occasion to put the holders within touching distance of the final again.
The Portugal forward headed Real in front on 10 minutes, although he appeared to have been offside in the initial build-up.
There was, though, no controversy about Ronaldo's second goal with 17 minutes left as he lashed the ball in from the edge of the Atletico penalty area.
Ronaldo completed his hat-trick for the second successive Champions League fixture when he swept in Lucas Vazquez's cut-back on 86 minutes.
Atletico, beaten in last season's final by Real, rarely threatened and now have it all to do at the Vicente Calderon next Wednesday night.
How did we rate the players in Madrid's emphatic derby win? Take a look at the gallery above to find out.
Do you agree with our ratings? Who was your man of the match? Let us know in the comments...Reuse content