We were all shocked. I've seen and done thousands of autopsies on horses, and nothing I'd ever seen compared to it. The heart of the average horse weighs about nine pounds. This was almost twice the average size, and a third larger than any equine heart I'd ever seen. And it wasn't pathologically enlarged. All the chambers and the valves were normal. It was just larger. I think it told us why he was able to do what he did. - Thomas Swerczek (Sports Illustrated 1990)
I was at Secretariat's Derby, in '73 ... That was ... just beauty, you know? He started in last place, which he tended to do. I was covering the second-place horse, which wound up being Sham. It looked like Sham's race going into the last turn, I think. The thing you have to understand is that Sham was fast, a beautiful horse. He would have had the Triple Crown in another year. And it just didn't seem like there could be anything faster than that. Everybody was watching him. It was over, more or less. And all of a sudden there was this, like, just a disruption in the corner of your eye, in your peripheral vision. And then before you could make out what it was, here Secretariat came. And then Secretariat had passed him. No one had ever seen anything run like that—a lot of the old guys said the same thing. It was like he was some other animal out there - Sportswriter Mike Sullivan
Secretariat continued the fast pace and opened up a larger and larger margin on the field. His time for the mile was 1:341⁄5, over a second faster than the next fastest Belmont mile fraction in history, set by his sire Bold Ruler, who had eventually tired and finished third. Secretariat, however, did not falter.
This horse really paced himself. He is smart: I think he knew he was going 1+1⁄2 miles, I never pushed him. - Ron Turcotte (Jockey)