The victory ensures Madrid, who have now won nine of their 11 competitive games under Jose Mourinho and drawn the other two, remain top of La Liga.
Ronaldo warned it is still early days though, saying in AS: "We need to continue fighting, there is still a lot of the season left and we need to continue improving."
Ronaldo also insisted his side need to focus on themselves rather than on arch-rivals Barcelona, who have yet to hit top form this season but nevertheless are just a point behind the capital club.
"There's no need to think of the others, we need to think of us. To continue as we have been doing, playing well and scoring a lot of goals. We don't have to be concerned with Barcelona," Ronaldo added.