While Ronaldo has been scoring goals for fun against the majority of La Liga outfits, the Portuguese schemer has struggled to make the same sort of impact against Pep Guardiola's charges.
53-year-old Sanchez feels that Ronaldo has to be coaxed and molly cuddled by tactician Jose Mourinho in order to hit his devastating peak.
"Cristiano Ronaldo has to be cuddled and pampered. You have to be careful with him and spoil him," said Sanchez in an interview with RNE.
"We all know his character, so we can't act surprised now all of a sudden. He's always needed support, and gets that affection from his coach."
"If he can start scoring goals again then the fans will soon share the coach's feelings again."
Madrid are set to clash with the Catalan giants at the Santiago Bernabeu in Wednesday's first-leg Copa del Rey quarterfinal encounter.