The 27-year-old did not appear to have to put his club's rivalry with the Blaugrana behind him in the off-season as he ignored the request for an autograph from a little girl
In a letter published by Portuguese paper Record, Robert Filipe says that his daughter had decided to wear Barca's shirt for her club's training in Obidos.
However, the practice session was cancelled because of the Portugal national team's preparations for Euro 2012, and the 10-year-old decided to take the opportunity to watch the players in action - only to be ignored by the Seleccao's biggest star.
"When I went to pick her up, I did not find the happy and cheerful girl that I expected, but a sad one," Filipe explained.
"When I asked her what was going on, she simply shrugged and said: 'Cristiano did not want to sign me an autograph because I am wearing Barcelona's shirt'.
"I did not know what to say. This is the shirt that she had put on to go to practice and that her mother had bought her when she visited Barcelona. It was the symbol of love and nothing else (had she visited Madrid the shirt would have obviously been different), and ended up causing her great sadness.
"My pain is to look at my daughter's eyes and see great disappointment in them and try to explain to a 10-year-old the reason a player of the national team, who she has been cheering for these last two weeks, going to every training session, had turned his back on her."
Portugal, who will play a pre-Euro friendly against Turkey on Saturday, will take on Germany, Denmark and Netherlands in Poland and Ukraine.
Since March, Goal.com has been publishing exclusive extracts from Luca Caioli's new book, Ronaldo: The Obsession for Perfection. This Friday's excerpt looks at how Cristiano and Portugal lost out in the final of Euro 2004. Don't miss it!
Watch Portugal live as they build up to Euro 2012 with their friendly against Turkey on Saturday