Sergio Ramos understands why Real Madrid fans have been whistling Cristiano Ronaldo this campaign and has told his team-mate any criticism should serve as a motivation to improve.


The Portugal international has been jeered on more than one occasion this term, most notably when Madrid struggled to find their best form during the first half of the season.


Ramos has told Ronaldo not to let any jeers affect him, though, as he is not the first high-profile name to be subjected to criticism from the Santiago Bernabeu faithful.


"I can understand that people whistle Cristiano. Why not? They have also whistled me, they whistled Manolo Sanchis, [Jose Antonio] Camacho, [the Brazilian] Ronaldo, [Zinedine] Zidane. The fans have whistled everyone," Ramos told COPE.


"There is always a reason for it when you get this kind of attention from the fans. You should always look at the positive side of things. The fans might think you can do a bit more and their whistles can lead to a reaction, to help you get the best out of yourself. And then everybody is happy again.


"I would never sell Cristiano, not for all the money in the world."


The prolific attacker picked up a minor knock in Madrid's win over Villarreal in midweek and could miss this weekend's trip to Rayo Vallecano, but Ramos is hopeful he will be fit in time for the Champions League semi-final clash with Manchester City.


"We hope that Ronaldo can play against City. We all know how important he is to the team," Ramos added.


"We hope it is nothing serious and that he will be there in the most important game of the season.


"We all know him, he is super ambitious. He always wants to play and score goals, even when he is asleep."