The former defender was part of the France squad that won the World Cup on home soil in 1998, before going on to lift the UEFA European Championships trophy two years later with an extra-time win over Italy in a dramatic final.
Desailly has since seen that achievement bettered by a dominant Spanish outfit, who have won three consecutive major tournaments between 2008 and 2012, playing an attractive, possession-based style of football.
Should they go on and make it four in a row by defending their world title won in South Africa four years ago, Desailly believes they will undoubtedly become the greatest international side of all time.
"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."
