"The best thing to take on Spain would be to allow us to play with 22 players instead of 11," Valdes joked in Tuesday's Spanish sports daily Marca.
"Against Spain it is absurd to think of it as just another day and just another team.
"You can't take them head on. Everything we try to do in games will have to doubled. Twice the attention, the concentration, the effort, helping each other out and so on."
Chelsea's Juan Mata, who was left out of the last three Spain squads, is back in the side and had words of praise for Panama coach Valdes.
"Dely Valdes played for Real Oviedo," Mata told a news conference, referring to the Spanish club where he started his playing career.
"I have seen goals he scored in their Tartiere stadium. He is the image of football in this country and I am sure he will imbue his team with the same footballing spirit he had."
