Deco is looking forward to the first Clasico of the season on Saturday.
Deco says there are really no favourites in El Clasico.
The former Portugal international, who spent four years at the Camp Nou, winning two LaLiga titles and the Champions League in 2006, doesn't think Barcelona or Real Madrid's current form would matter heading into the match on Saturday.
"I think it is the greatest football match of all time," he told Omnisport. "That is why the whole world's eyes are on it. For me, it is the best football match in the world.
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"In El Clasico there is no favourites, because it depends on how the teams are. In El Clasico, anything can happen.
"I don't see a favourite, both are great teams. The first time we played [El Clasico] in Barcelona [in November 2004], we won 3-0. For us, it was the change of a century, and the end of Real Madrid's domination.
"We won 3-0 at home and it was a really important victory. Our time in football is past, we enjoyed it, and now we have to enjoy watching other players."
Luis Enrique's side are six points behind their bitter rivals Los Blancos at the top of the table heading into the Clasico as they look to end Madrid's 32-match unbeaten run in all competitions.