Pancho Gonzales
I agree that Lacoste was a bit behind Big Bill until 26 or so.Kramer was very good during the first half of the 50´s, 1950-54; then Hoad,Rosewall,Gonzales and Trabert ( and of course Sedgman) took it over from him.
I think Sedgman hit peak during 1953, as indicated by his drubbing of Gonzales in two major finals.