Cristiano Ronaldo has suffered a dip in form that has prompted a backlash from some Madrid fans, but the Portuguese is not bothered by criticism.

Speaking ahead of Madrid's crucial Copa del Rey quarter-final second leg against Celta Vigo at Balaidos, the 31-year-old says he has no interest in trying to win over his critics.

"It doesn't matter to me. I just try to do my job. Everyone has people they hate, it's not only me. It's part of the job," he said.

"I go to bed every day in a good mood. I sleep well every night. I'm not here to make my detractors happy, I'm here to make my supporters happy, the ones who show me respect and affection, who are with me all the time. That's the most important thing for me."