| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 1. Szabo vs J Klein |
| 1-0 | 18 | 1960 | Santa Fe | A71 Benoni, Classical, 8.Bg5 |
| 2. J Klein vs H Rossetto |
| 0-1 | 31 | 1960 | Santa Fe | B32 Sicilian |
| 3. M A Casabella vs J Klein |
| ½-½ | 20 | 1960 | Santa Fe | B41 Sicilian, Kan |
| 4. J Klein vs Gligoric |
 | 0-1 | 23 | 1960 | Santa Fe | B28 Sicilian, O'Kelly Variation |
| 5. Korchnoi vs J Klein |
| 1-0 | 33 | 1960 | Santa Fe | A65 Benoni, 6.e4 |
| 6. J Klein vs F Casas |
| 1-0 | 38 | 1960 | Santa Fe | A87 Dutch, Leningrad, Main Variation |
| 7. J Klein vs Taimanov |
| 0-1 | 21 | 1960 | Santa Fe | E91 King's Indian |
| 8. Filip vs J Klein |
| 1-0 | 40 | 1961 | Santa Fe | A65 Benoni, 6.e4 |
| 9. M A Casabella vs J Klein |
| ½-½ | 29 | 1961 | Santa Fe | E43 Nimzo-Indian, Fischer Variation |
| 10. J Klein vs A Matanovic |
| 0-1 | 25 | 1961 | Santa Fe | D02 Queen's Pawn Game |
| 11. H Rossetto vs J Klein |
| 1-0 | 42 | 1961 | Santa Fe | A34 English, Symmetrical |
| 12. J Klein vs Letelier |
| 0-1 | 41 | 1961 | Santa Fe | A40 Queen's Pawn Game |
| 13. R Byrne vs J Klein |
| 1-0 | 32 | 1961 | Santa Fe | A60 Benoni Defense |
| 14. J Klein vs C Bielicki |
| 1-0 | 33 | 1961 | Santa Fe | E81 King's Indian, Samisch |
| 15. J Klein vs B Marcussi |
| 1-0 | 26 | 1963 | ARG-ch | B94 Sicilian, Najdorf |
| 16. M de Athayde vs J Klein |
| 1-0 | 37 | 1963 | Fortaleza Zonal | A60 Benoni Defense |
| 17. J Klein vs E Asfora |
| 0-1 | 19 | 1963 | Fortaleza Zonal | B32 Sicilian |
| 18. O Quinones Carrillo vs J Klein |
| 1-0 | 73 | 1963 | Fortaleza Zonal | B28 Sicilian, O'Kelly Variation |
| 19. J Klein vs H Rossetto |
| 0-1 | 22 | 1963 | Fortaleza Zonal | C12 French, McCutcheon |
| 20. R Garcia vs J Klein |
| 1-0 | 29 | 1963 | Fortaleza Zonal | A07 King's Indian Attack |
| 21. J Klein vs R Camara |
| 0-1 | 45 | 1963 | Fortaleza Zonal | B77 Sicilian, Dragon, Yugoslav Attack |
| 22. J F Olivera vs J Klein |
| 0-1 | 33 | 1963 | Fortaleza Zonal | D02 Queen's Pawn Game |
| 23. J Klein vs A Foguelman |
| ½-½ | 25 | 1963 | Fortaleza Zonal | C14 French, Classical |
| 24. J Klein vs A C Rocha |
| 0-1 | 44 | 1963 | Fortaleza Zonal | B06 Robatsch |
| 25. C Espinoza Rivasplata vs J Klein |
| ½-½ | 45 | 1963 | Fortaleza Zonal | A60 Benoni Defense |
Kibitzing
