Ronaldo, 33, departed Real in the off-season in a club-record sale and left with a legendary status as the club's all-time record scorer.
Under the guidance of Julen Lopetegui, it seemed the European champions were galvanised through his absence, with Karim Benzema and Gareth Bale firing on all cylinders.
But a run of four games without a goal across all competitions has left the new manager and the squad under severe pressure.
While Nacho acknowledged the legacy of Ronaldo, he admits it's necessary for the CR7 era to be forgotten.
"At the start of the season, we scored lots of goals," he told EFE, as quoted by AS. "And nobody remembered Cristiano Ronaldo, who started at Juventus without scoring a goal and they said that after leaving Real Madrid, he stopped scoring. In football, everything is changing.
"Cristiano was a very important player for us. In the end, he scored 50 goals a season, but we're not the ones to blame and we can't cry over what happened in the past.
"We have to move forward with what we have, that is with a very good squad and we are prepared for everything."