6 rounds

Sonny
Williams
VS
Marvelous
Marvin Hagler

Hagler · UD 6/6

Jul 25, 1973 · Boston Arena, Boston, Massachusetts, 🇺🇸

Williams going in—

Hagler going in1-0-0

Confirmation✓ one source

MethodUD

Round6 of 6

Sources

English Wikipedia
side b · observed 2026-10-11
en.wikipedia.org/wiki/Marvelous_Marvin_Hagler

✓

✓