Despite losing the second leg of their quarter-final tie, Los Blancos progressed to the semi-finals of the tournament with a 5-3 aggregate win.
However, Ronaldo feels that his side must not let complacency creep in for future games after they came closer than expected to squandering their 3-0 lead from the first leg played in Madrid last week.
"This match will serve as an example for us in the future," Ronaldo told UEFA.com.
"We're happy to get through after this difficult game. They made things hard but in reality we were the ones who made things complicated for ourselves."
Madrid are aiming to win their 10th European Cup this season.