Ronaldo's strike eight minutes from time secured Real Madrid a 2-2 draw with Atletico Madrid at Estadio Vicente Calderon to remain three points clear of their fierce city rivals at the top of the Primera Division.
Atletico looked on course for the derby bragging rights after first-half strikes from Koke and Gabi had put them ahead following Karim Benzema's early opener for Real.
But Ronaldo lashed home in the 82nd minute to the relief of boss Carlo Ancelotti and deny Atletico's hopes of completing a league double over their more celebrated rivals for the first time since 1951, having beaten them at the Bernabeu 1-0 earlier in the season.
Ancelotti said: "We drew a game that we were losing. The response was good and overall we can be satisfied because Atlético are a good team, particularly at home. We're top and that's good. Now we have seven games at home and five away.
"A point is a point. It was a difficult match."
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