| Premier League 2021 Championship - Appearances as Assistant | ||||
| 01/05/2021 | Coleraine FC | - | Cliftonville FC | 2:0 |
| 04/05/2021 | Linfield FC | - | Crusaders FC | 3:1 |
| 25/05/2021 | Larne FC | - | Glentoran FC | 0:1 |
| 25/05/2021 | Coleraine FC | - | Linfield FC | 1:1 |
| Premier League 2021 Championship - Appearances as Assistant | ||||
| 01/05/2021 | Coleraine FC | - | Cliftonville FC | 2:0 |
| 04/05/2021 | Linfield FC | - | Crusaders FC | 3:1 |
| 25/05/2021 | Larne FC | - | Glentoran FC | 0:1 |
| 25/05/2021 | Coleraine FC | - | Linfield FC | 1:1 |
| Complete name: | Mark O'Brien |
| Born: | |
| Place of birth: |
Northern Ireland |
| Nationality: |
Northern Ireland |