Billy O'Brien (Willie) boxer
- bouts
- 5
- won
- 0
- lost
- 4
- draw
- 1
- Status
- inactive
- Division
- -
- Debut
- 1900-10-04
- Height
- -
- Reach
- -
- Age
- -
- Born
- -
- Death
- -
- Nationality
- USA
| Date | Opponent | Last Opponents' Results | Place | Result |
|---|---|---|---|---|
| 1902-07-30 | George Ellis | LL | Mechanics' Pavilion Annex, San Francisco | LOST KO |
| 1902-05-07 | Johnny Crowe | LDWW | Mechanics' Pavilion Annex, San Francisco | LOST Points |
| 1900-10-04 | Charles Anderson | debut | San Francisco A.C., San Francisco | DRAW Points |