From way back on April 22, 1969, at the Sam Houston Coliseum in Houston.
This was quite a mismatch. Zyglewicz was 28-1 against journeymen, a guy who was fighting as the hometown hero in Houston, though he was born in Troy, NY. Frazier, at 22-0, had already beaten some good fighters, was a champion, and was just the nastiest hooker around -- which sounds funny, if you don't read it in boxing language.
Frazier was two years away from his first fight with Muhammad Ali. Zyglewicz never had another major fight.
Sometimes people wonder why the heavyweights don't trade like the old guys used to, but it's pretty simple. Joe Frazier weighed 204 1/2 pounds for this fight, and Zyglewicz was at 190 1/2. We're talking about cruiserweights, essentially. The heavyweight division isn't what it used to be because it literally is not what it used to be.