| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. J Dueball vs L Mista |
| 1-0 | 39 |
1968 |
WchT U26 15th fin-A | B35 Sicilian, Accelerated Fianchetto, Modern Variation with Bc4 |
| 2. J Dueball vs Kolbak |
| 1-0 | 41 |
1968 |
WchT U26 15th fin-A | B11 Caro-Kann, Two Knights, 3...Bg4 |
| 3. D Metras vs J Dueball |
| 0-1 | 55 |
1968 |
WchT U26 15th qual-B | A02 Bird's Opening |
| 4. A Babev vs J Dueball |
| 1-0 | 35 |
1968 |
WchT U26 15th qual-B | E81 King's Indian, Samisch |
| 5. D Zara vs J Dueball |
| 0-1 | 30 |
1968 |
WchT U26 15th fin-A | A48 King's Indian |
| 6. J Dueball vs Ivkov |
| ½-½ | 43 |
1969 |
Raach zt | C86 Ruy Lopez, Worrall Attack |
| 7. P Atanasov vs J Dueball |
 | 1-0 | 24 |
1969 |
Dresden | D85 Grunfeld |
| 8. Hecht vs J Dueball |
| ½-½ | 16 |
1969 |
Raach | A88 Dutch, Leningrad, Main Variation with c6 |
| 9. Portisch vs J Dueball |
| 1-0 | 42 |
1969 |
Raach | A56 Benoni Defense |
| 10. O Jakobsen vs J Dueball |
| ½-½ | 31 |
1969 |
Raach zt | A04 Reti Opening |
| 11. J Dueball vs Uhlmann |
 | 0-1 | 30 |
1969 |
Raach | C18 French, Winawer |
| 12. J Dueball vs Smejkal |
| 0-1 | 47 |
1969 |
Raach zt | C11 French |
| 13. Tseshkovsky vs J Dueball |
 | 0-1 | 30 |
1969 |
WchT U26 fin-A 16th | B57 Sicilian |
| 14. J Dueball vs G Sigurjonsson |
| 1-0 | 41 |
1969 |
Raach zt | C16 French, Winawer |
| 15. J Dueball vs A Matanovic |
| 0-1 | 46 |
1969 |
Raach zt | B06 Robatsch |
| 16. Ulf Andersson vs J Dueball |
| ½-½ | 26 |
1969 |
Raach zt | B25 Sicilian, Closed |
| 17. V Tukmakov vs J Dueball |
| ½-½ | 24 |
1970 |
Ukraine-Berlin West m | A31 English, Symmetrical, Benoni Formation |
| 18. V Tukmakov vs J Dueball |
| 1-0 | 42 |
1970 |
Ukraine-Berlin West m | D93 Grunfeld, with Bf4 & e3 |
| 19. J Dueball vs Huebner |
| 0-1 | 36 |
1970 |
Berlin Silvester Tt | B06 Robatsch |
| 20. J Dueball vs V Tukmakov |
| ½-½ | 26 |
1970 |
Ukraine-Berlin West m | C86 Ruy Lopez, Worrall Attack |
| 21. J Dueball vs I Bilek |
| ½-½ | 33 |
1970 |
Bad Pyrmont | B06 Robatsch |
| 22. J Dueball vs O'Kelly |
| 1-0 | 57 |
1970 |
BRD | C95 Ruy Lopez, Closed, Breyer |
| 23. J Dueball vs V Tukmakov |
| ½-½ | 35 |
1970 |
Ukraine-Berlin West m | C95 Ruy Lopez, Closed, Breyer |
| 24. Ulf Andersson vs J Dueball |
 | 1-0 | 55 |
1971 |
West Berlin (Germany) | B27 Sicilian |
| 25. M Damjanovic vs J Dueball |
| ½-½ | 15 |
1971 |
FRG-ch int | C85 Ruy Lopez, Exchange Variation Doubly Deferred (DERLD) |