Barca equalled a 51-year-old club record for their biggest away victory in La Liga by demolishing Almeria 8-0 at the Estadio de los Juegos Mediterraneos.
That result saw Pep Guardiola's side briefly take over top spot in La Liga, but Madrid reclaimed pole position after thumping Athletic Bilbao 5-1 at the Bernabeu in the evening's late match.
Ronaldo appeared far from concerned about Barca's result, saying: "The 8-0 at Almeria doesn't tell me anything, lets see if they score eight goals against us on Monday."
Aside from pitting the top two teams in La Liga against each other, El Clasico should also see the two leading goalscorers in the division go head to head.
Despite that impressive tally, Ronaldo insists his main aim for the season is team success rather than individual glory.
He said: "We are very happy for the win and I'm also very happy for scoring three goals, but the important thing is that we continue being leaders.
"I'm fighting to win the league, not for the Pichichi (leading goalscorer in La Liga)."