| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. K O'Riordan vs E N Mulcahy |
| 0-1 | 17 |
1954 |
IRL Ch | D25 Queen's Gambit Accepted |
| 2. J Moles vs K O'Riordan |
| 1-0 | 25 |
1966 |
IRL-ch | B49 Sicilian, Taimanov Variation |
| 3. A Dennehy vs K O'Riordan |
| 1-0 | 31 |
1967 |
IRL-ch | C97 Ruy Lopez, Closed, Chigorin |
| 4. K O'Riordan vs W Heidenfeld |
| 0-1 | 32 |
1967 |
IRL-ch | A85 Dutch, with c4 & Nc3 |
| 5. K O'Riordan vs A Magrin |
| 0-1 | 32 |
1968 |
Lugano Olympiad | E14 Queen's Indian |
| 6. G Koshnitsky vs K O'Riordan |
| 1-0 | 30 |
1968 |
Lugano Olympiad | A98 Dutch, Ilyin-Genevsky Variation with Qc2 |
| 7. G Budowski vs K O'Riordan |
| 1-0 | 25 |
1968 |
Lugano Olympiad | C08 French, Tarrasch, Open, 4.ed ed |
| 8. K O'Riordan vs R Quesada Jr |
| 0-1 | 31 |
1968 |
Lugano | B70 Sicilian, Dragon Variation |
| 9. G Barcza vs K O'Riordan |
| 1-0 | 22 |
1968 |
Lugano Olympiad | A04 Reti Opening |
| 10. Suttles vs K O'Riordan |
| 1-0 | 45 |
1968 |
Lugano | A00 Uncommon Opening |
| 11. K O'Riordan vs V Riego |
| 0-1 | 41 |
1968 |
Lugano Olympiad | B82 Sicilian, Scheveningen |
