The result ended a run of four consecutive defeats by Atletico.
Atleti leapfrogged Rayo in the standings and are now fourth with 32 points from 19 matches. Rayo is fifth, with 30 points. Real Madrid, who lost at Getafe earlier, leads LaLiga with 46 points from 20 games.
"After four consecutive losses, we needed this win," man-of-the-match Correa told reporters.
"It's a great way to start the year because we won playing well, dominating; we are really happy with the attitude and the result."