The benchmark of 18 was set by the iconic Alfredo Di Stefano, widely considered to be the greatest player in Madrid's illustrious history.
Ronaldo drew level with Di Stefano on Sunday by turning home from inside the six-yard box after Karim Benzema nodded a delivery from Toni Kroos across the face of goal.
His effort cancelled out Luis Suarez's opener at Camp Nou, as Madrid attempt to stop the champions from finishing their La Liga season unbeaten.
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18 - Cristiano Ronaldo has equalled Alfredo Di Stefano as the all-time Real Madrid top-scorer in El Clasico in all competitions. Legends. pic.twitter.com/kXmQezNqZT — OptaJose (@OptaJose) May 6, 2018