| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. DeFirmian vs J L Arnason |
| 0-1 | 31 |
1973 |
Bunadarbanka (Iceland) | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
| 2. DeFirmian vs Christiansen |
| 1-0 | 46 |
1979 |
Lone Pine (USA) | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
| 3. DeFirmian vs Ivkov |
| 1-0 | 44 |
1981 |
Baden-Baden (Germany) | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
| 4. DeFirmian vs Ye Rongguang |
| 1-0 | 37 |
1989 |
Ch World (team) | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
| 5. DeFirmian vs Portisch |
| ½-½ | 64 |
1990 |
Manila (Philippines) | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
| 6. DeFirmian vs Timman |
| ½-½ | 40 |
1996 |
Memorial Donner (cat.16) | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
| 7. DeFirmian vs Timman |
| ½-½ | 31 |
2000 |
Reykjavik op19 | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
| 8. DeFirmian vs H Greiff |
| 1-0 | 41 |
2001 |
Politiken Cup | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
| 9. DeFirmian vs I Sokolov |
 | 0-1 | 31 |
2003 |
2nd Milk Tournament | C72 Ruy Lopez, Modern Steinitz Defense, 5.O-O |
