Ricardo Carvalho has hailed Cristiano Ronaldo as "almost perfect" as his Portugal teammate goes up against Ballon D'Or rival Lionel Messi of Argentina in a friendly at Old Trafford on Tuesday.

Real Madrid forward Ronaldo, who knows Old Trafford well from his time with Manchester United, is the current holder of the the world's best player award.

Inevitably, the pair have been the focus of attention in the build-up to the game and Monaco defender Carvalho told a media conference on Monday: "It is normal about the game to speak about Cristiano and Messi but I think it is Portugal against Argentina.

"For us Portuguese, everyone is expecting that Cristiano can win his third Golden Ball (Ballon D'Or). I am a little bit biased but I think he is the best.

"We are so proud of him. He is doing a great job during this past six or seven years. He is improving all the small details, making so many goals.

"He is looking always to try his best. It is difficult because when you see him, he is almost perfect, strong, good in the air, fit always. It is difficult to say what he is missing," Carvalho said.

"There is no reason for him not to win (for) the third time."

Agence France-Presse