The former Blaugrana star spent time playing with the Argentine before joining Chelsea in 2008 and thinks that Tito Vilanova has perfected how the Catalunya club play.
"Their style of play won’t change," Deco said. "That’s cultural, that’s how they think football. What can change is how good you portray style on the pitch.
"Nowadays, Barcelona can almost reach perfection with this style of playing because of the players they have. And they also have a footballer who is the cherry on top of the cake. Messi is able to make this already very good team be something else."
Deco also played with Real Madrid forward Cristiano Ronaldo during his time as a Portugal international but is of the opinion that the former Manchester United man and Messi should not be compared.
"It is a natural comparison because they are far away in front of other players, and for media it is a fantastic subject. But I think it is unfair to compare as they have different styles, and are so good with their styles, that it would be unfair to judge who is better," he added."
"Last year, Cristiano was better in the first six months, I mean he had better stats, but in the final part Messi got better with his. How can you judge this? I don’t know, it is hard, one has a rare quality. The other has a unique mentality that will never happen again in football. So it is difficult to say.”
"I saw ‘Cris’ doing impressive things for the national team at a very young age. Cristiano impressed me with his winning mentality since he was very young, even more because of the family problems that he had and he had to live by himself early, he is an example of a person who overcame problems and we must admire this.
"His story should suggest a complicated end, but he did the best of it. He has a winning mentality that honest I have never seen. I have never met a player even with a closer mentality that the one he has."
Deco's career was given an enormous boost while part of the Porto team which stormed the Champions League under Jose Mourinho and the attacker praised his Portuguese compatriot for the way he influences his squads.
"Mourinho was the coach in which I really saw something different. He controls everything that involves football," the 35-year-old continued.
"It is not only match and training, he understands the way players behave, he is in control of everything is happening around the game, and these things make footballers more secure.
"My experience with Mourinho was in Porto, and without him we could never have done that extra step, he brought us a winning mentality, a confidence, a feeling that we could go further."