The Spanish club are on a tour to China designed to promote the Real brand in the world's second biggest economy and tap into the burgeoning wealth of its 1.3 billion population, where football and European clubs are hugely popular.
But some observers said Ronaldo's behaviour at the press conference on Tuesday in the major southern city of Guangzhou—where he gave often mumbled one-sentence answers—could have the very opposite effect.
"He always seems selfish and arrogant," said Yan Qiang, vice-president of Titan Media, one of China's leading sports publishers, noting the flying winger is one of the most popular players in China, along with Kaka and Lionel Messi.
"His behaviour won't help his cause in China," Yan told AFP, suggesting that the negative reaction to his appearance on the eve of a friendly with Guangzhou Evergrande might also hurt the prospects in China of his backers Nike.
Asked at the press briefing about the condition of his injury-prone teammate Kaka, Ronaldo, who became the world's most expensive player when he left Manchester United for Real in 2009 for £80 million, answered: "Perfecto."
In an attempt to lift the mood, another Chinese journalist asked Ronaldo, who last year became a father, whether he changed his son's nappy.
"Of course, as a father it is normal to change the baby's nappies," an unamused Ronaldo replied in English.
And asked by AFP if he might ever return to United or English football, he said: "Maybe, why not? You never know."
He was also quizzed about his interest in table tennis and whether he knew any of the Chinese players. Asked later about his impressions of Guangzhou, he said that it was very hot.
"The questions he was asked didn't have much to do with football. Chinese fans are different from European fans. Chinese are more into the personal lives of their icons," Yan said.
China's massive Internet population—the world's largest at 485 million—also got stuck into the 26-year-old Portuguese.
"I don't know whether Ronaldo can be the World Footballer of the Year, but I am just sure he will be condemned for what he did at the news conference," web user "wangjihe" wrote on the sports channel of popular web portal Netease.
"Ronaldo is really good at football, and good-looking, but he is really not that modest," wrote another fan on the website, using the number 7726693116 as a web handle.
"He should hire a public relations company to teach him how to cope with the media."
A third observer, named 9513638962, was more blunt, writing simply: "Look at you! C. Ronaldo, just go home!"
Real's promotional tour in China next moves to the city of Tianjin, close to Beijing.