The 33-year-old has now written his autobiography, to be published in the New Year, recounting his journey from Paris to Goodison Park.
Saha said of the Real Madrid star: "There is not a more complete player in the world.
"He could play in any position. He will always score because he runs quicker and jumps higher than everyone. His endurance is crazy - his power of shot as well.
"He would score 30 goals in any team, because he can do it all on his own. Messi is maybe the best player in the world, but I am convinced he has need of the team to play."