| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. Larsen vs A Nielsen |
 | 1-0 | 29 |
1953 |
Nordic Championship | A31 English, Symmetrical, Benoni Formation |
| 2. G Lorson vs A Nielsen |
| ½-½ | 32 |
1954 |
Amsterdam ol (Men) | A15 English |
| 3. G Lorson vs A Nielsen |
| ½-½ | 21 |
1954 |
Amsterdam ol (Men) | A32 English, Symmetrical Variation |
| 4. A Nielsen vs G Porreca |
| 0-1 | 27 |
1954 |
Amsterdam ol (Men) | D48 Queen's Gambit Declined Semi-Slav, Meran |
| 5. A Nielsen vs P Trifunovic |
| ½-½ | 57 |
1954 |
Amsterdam ol (Men) | A30 English, Symmetrical |
| 6. B De Greiff vs A Nielsen |
| 1-0 | 42 |
1954 |
Amsterdam ol (Men) | B50 Sicilian |
| 7. A Nielsen vs T Store |
| 0-1 | 68 |
1954 |
Amsterdam ol (Men) | D31 Queen's Gambit Declined |
| 8. A Nielsen vs M Raizman |
| 1-0 | 50 |
1954 |
Amsterdam ol (Men) | A16 English |
| 9. F R Anderson vs A Nielsen |
| 1-0 | 59 |
1954 |
Amsterdam ol (Men) | C05 French, Tarrasch |
| 10. A Nielsen vs A Neu |
| 1-0 | 40 |
1954 |
Amsterdam ol (Men) | A17 English |
| 11. V Maher vs A Nielsen |
| 0-1 | 74 |
1954 |
Amsterdam ol (Men) | D19 Queen's Gambit Declined Slav, Dutch |
| 12. A Nielsen vs A Vestol |
| 1-0 | 48 |
1954 |
Amsterdam ol (Men) | A16 English |
| 13. M Czerniak vs A Nielsen |
| ½-½ | 40 |
1954 |
Amsterdam ol (Men) | B70 Sicilian, Dragon Variation |
| 14. J Anagnostou vs A Nielsen |
| ½-½ | 41 |
1954 |
Amsterdam ol (Men) | D32 Queen's Gambit Declined, Tarrasch |
| 15. A Nielsen vs A Beni |
 | 0-1 | 79 |
1954 |
Amsterdam ol (Men) | A16 English |
| 16. A Nielsen vs Larsen |
 | 0-1 | 71 |
1955 |
DEN-ch | A04 Reti Opening |
| 17. A Nielsen vs J Sefc |
| 1-0 | 75 |
1956 |
Moscow ol (Men) fin-A | A14 English |
| 18. A Nielsen vs Larsen |
| 0-1 | 30 |
1956 |
Copenhagen | A21 English |
| 19. A Nielsen vs Portisch |
| 0-1 | 63 |
1956 |
Moscow | C01 French, Exchange |
| 20. A Nielsen vs Ivkov |
| 0-1 | 34 |
1956 |
Moscow | A22 English |
| 21. A Nielsen vs I Johannsson |
| 0-1 | 41 |
1956 |
Copenhagen | B88 Sicilian, Fischer-Sozin Attack |
| 22. A Nielsen vs Larsen |
| ½-½ | 47 |
1959 |
DEN-ch | A04 Reti Opening |
| 23. Tal vs A Nielsen |
 | 1-0 | 27 |
1960 |
Stockholm | A84 Dutch |
| 24. J Enevoldsen vs A Nielsen |
| 1-0 | 68 |
1960 |
Ch Denmark, Aalborg (Denmark) | B16 Caro-Kann, Bronstein-Larsen Variation |
| 25. A Nielsen vs H Nielsen |
| 1-0 | 41 |
1960 |
Ch Denmark, Aalborg (Denmark) | A22 English |