The former France star says Vicente del Bosque's side will surpass the achievements of every national side in the game's history if it retains the crown in Brazil.
Marcel Desailly believes Spain will go down as the greatest national side of all-time if it wins the World Cup.
The former defender was part of the France squad that won the tournament on home soil in 1998, before going on to lift the European Championship trophy two years later with an extra-time win over Italy.
Desailly has since seen that achievement bettered by a dominant Spain outfit, which has won three consecutive major tournaments between 2008 and 2012, playing an attractive, possession-based style of football.
"If Spain win the World Cup it will be an amazing moment," he said. "They will be for sure the best national team of history. We had the opportunity to go for the second one with France and we know how difficult it is to handle the pressure.
"But Spain collectively, tactically, they have the players. Even if you have some players whose performance goes down, they have so many young players coming up - [Alvaro] Negredo and [Santi] Cazorla for example - who can fit into the system.
"I will be very interested to see how Spain handle this, because we know everything about them, but still they surprise us and they are able to deliver every time very good games and performances."
Spain will play friendlies against Bolivia and El Salvador before starting its World Cup campaign against the Netherlands on June 13.
Vicente del Bosque’s men, who have been drawn in in Group B, will then face Chile and Australia as they bid to reach the knockout stages.