All the finest Turf writers of their day wrote the Super Horse was a Super Horse during its career. As an elderly woman I have been reading that for some decades now. I recall the cover of Sports Illustrated having Secretariat`s picture on it BEFORE his Belmont Stakes win. The title read Super Horse.
Man O War got all the same Super Horse praise during his racing days. Man O War set more records than Secretariat in harsher circumstances and Man O War has actual faster internal splits in a race than Secrertariat and MOW did it on cuppy slower holding tracks.
Both horses were called the Greatest ever well before they ended their careers.