| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. DeFirmian vs N J Patterson |
| 1-0 | 23 |
1978 |
London (England) | B97 Sicilian, Najdorf |
| 2. DeFirmian vs P Youngworth |
 | 1-0 | 43 |
1980 |
Lone Pine (USA) | B99 Sicilian, Najdorf, 7...Be7 Main line |
| 3. DeFirmian vs Marjanovic |
| 1-0 | 54 |
1983 |
Vrnjachka Banja (Yugoslavia) | B90 Sicilian, Najdorf |
| 4. DeFirmian vs Barlov |
| 1-0 | 30 |
1983 |
Vrnjachka Banja (Yugoslavia) | B93 Sicilian, Najdorf, 6.f4 |
| 5. DeFirmian vs Browne |
| ½-½ | 59 |
1983 |
Ch USA | B99 Sicilian, Najdorf, 7...Be7 Main line |
| 6. DeFirmian vs Tarjan |
| 1-0 | 33 |
1983 |
Ch USA | B94 Sicilian, Najdorf |
| 7. DeFirmian vs H Olafsson |
| ½-½ | 18 |
1983 |
Bunadarbanka (Iceland) | B93 Sicilian, Najdorf, 6.f4 |
| 8. DeFirmian vs G Sigurjonsson |
| ½-½ | 38 |
1984 |
Bunadarbanka (Iceland) | B93 Sicilian, Najdorf, 6.f4 |
| 9. DeFirmian vs Browne |
| ½-½ | 19 |
1984 |
US-ch | B93 Sicilian, Najdorf, 6.f4 |
| 10. DeFirmian vs R Byrne |
| ½-½ | 28 |
1984 |
US-ch | B93 Sicilian, Najdorf, 6.f4 |
| 11. DeFirmian vs Gavrikov |
| 0-1 | 71 |
1985 |
Tunis | B90 Sicilian, Najdorf |
| 12. DeFirmian vs A Salazar |
| 0-1 | 29 |
1986 |
Olympiad | B90 Sicilian, Najdorf |
| 13. DeFirmian vs S Sandager |
| 1-0 | 25 |
1987 |
New York (USA) | B93 Sicilian, Najdorf, 6.f4 |
| 14. DeFirmian vs Browne |
| ½-½ | 57 |
1987 |
Ch USA | B99 Sicilian, Najdorf, 7...Be7 Main line |
| 15. DeFirmian vs Richard Wade |
| 1-0 | 29 |
1989 |
National | B93 Sicilian, Najdorf, 6.f4 |
| 16. DeFirmian vs Gavrikov |
| ½-½ | 13 |
1989 |
Cup World (open) | B93 Sicilian, Najdorf, 6.f4 |
| 17. DeFirmian vs Ivanchuk |
| 0-1 | 34 |
1989 |
Ch World (team) | B90 Sicilian, Najdorf |
| 18. DeFirmian vs L Busquets |
| 1-0 | 28 |
1989 |
New York (USA) | B90 Sicilian, Najdorf |
| 19. DeFirmian vs Polugaevsky |
| ½-½ | 15 |
1990 |
Reykjavik (Iceland) | B96 Sicilian, Najdorf |
| 20. DeFirmian vs Ljubojevic |
| ½-½ | 20 |
1990 |
Manila (Philippines) | B93 Sicilian, Najdorf, 6.f4 |
| 21. DeFirmian vs E Tate |
| 1-0 | 51 |
1993 |
World Op A, Philadelphia | B90 Sicilian, Najdorf |
| 22. DeFirmian vs G Thorhallsson |
| 1-0 | 25 |
1994 |
Reykjavik open | B90 Sicilian, Najdorf |
| 23. DeFirmian vs Van Wely |
| ½-½ | 50 |
1994 |
Akureyri (Iceland) | B93 Sicilian, Najdorf, 6.f4 |
| 24. DeFirmian vs Kasparov |
| ½-½ | 58 |
1995 |
Intel Chess Grand Prix (active) | B90 Sicilian, Najdorf |
| 25. DeFirmian vs Wolff |
| ½-½ | 23 |
1995 |
Ch USA | B90 Sicilian, Najdorf |
