Cristiano Ronaldo of Real Madrid eyes the ball during their Champions League Group D soccer match against Dinamo Zagreb at the Maksimir stadium in Zagreb September 14, 2011.  [Photo/Agencies]

MADRID - Opposing fans give Real Madrid forward Cristiano Ronaldo a hostile reception because he is "rich, handsome and a great player," the Portuguese said after Wednesday's 1-0 Champions League win at Dinamo Zagreb.

Ronaldo, the world's most expensive signing, was roundly booed and whistled during the Group D opener in Croatia and was also the target of some robust challenges, one of which drew blood on his right ankle and required several stitches.

The 26-year-old was unhappy with referee Svein Oddvar Moen and said top players were not getting enough protection.

"We are very happy with three points we took, but I'm not so satisfied with the refereeing," he told reporters.

"I hope we never have this referee again. People talk of fair-play, of protecting good players, but I never get any of that. I don't understand a thing.

"I'm sad because I hear referees saying they will protect skilful players, but while some are untouchable it seems I can be mauled."

Ronaldo was asked about the behaviour of the Dinamo fans, who gave him the kind of unfriendly reception he endures week in week out in La Liga and chanted the name of his Barcelona rival and World Player of the Year Lionel Messi.

"I think that because I am rich, handsome and a great player people are envious of me," he said. "I don't have any other explanation."

Argentine winger Angel Di Maria scored for Jose Mourinho's side in the 53rd minute as Real began their quest for a 10th title in Europe's elite club competition.