6 rounds

Jack
Mahoney
VS
Philadelphia
Jack O'Brien

O'Brien · PTS 6/6

May 25, 1900 · Star Theatre, Chicago, 🇺🇸

Mahoney going in—

O'Brien going in31-5-14

Confirmation✓ one source

MethodPTS

Round6 of 6

Sources

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

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