Former Barcelona striker Hristo Stoichkov has claimed that Real Madrid forward Cristiano Ronaldo is obsessed with on-field rival Lionel Messi.

Ronaldo has appeared unsettled at Real following jeers from supporters at the Santiago Bernabeu during the recent victory over Levante, which came on the back of a turbulent few weeks for the club.

Stoichkov says that Ronaldo's attitude must improve if he is to help his team to win games and regain the support of the fans.

"You can't doubt the quality of either Ronaldo or Messi. Messi is where he should be and Cristiano is going through a difficult time but all players go through rough patches. I was whistled as well in my time. It's up to the coach to make decisions and to speak to the player," the Bulgarian told The Independent.

"Maybe the obsession with Messi is affecting him but I'm not inside his head. Messi motivates his teammates and, if Ronaldo doesn't score, it affects his team.

"At times like that you have to display your personality; 99% of players can't answer the question 'why am I being booed?' Messi is at the level of Pele, Diego Maradona and Johan Cruyff and what annoys Cristiano is that he is only compared to Messi."

Ronaldo has scored 41 goals in 39 appearances for Los Blancos in all competitions this season.