| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. I Mendivil vs O Gadia |
| ½-½ | 33 | 1963 | Fortaleza Zonal | B87 Sicilian, Fischer-Sozin with ...a6 and ...b5 |
| 27. J Klein vs I Mendivil |
| 1-0 | 26 | 1963 | Fortaleza Zonal | C22 Center Game |
| 28. I Mendivil vs A C Rocha |
| 0-1 | 41 | 1963 | Fortaleza Zonal | B95 Sicilian, Najdorf, 6...e6 |
| 29. M de Athayde vs I Mendivil |
| ½-½ | 35 | 1963 | Fortaleza Zonal | C78 Ruy Lopez |
| 30. I Mendivil vs E Asfora |
| 1-0 | 82 | 1963 | Fortaleza Zonal | C46 Three Knights |
| 31. O Quinones Carrillo vs I Mendivil |
| ½-½ | 54 | 1963 | Fortaleza Zonal | C95 Ruy Lopez, Closed, Breyer |
| 32. I Mendivil vs H Rossetto |
| 0-1 | 30 | 1963 | Fortaleza Zonal | B00 Uncommon King's Pawn Opening |
| 33. I Mendivil vs F Castillo Tamariz |
| 1-0 | 56 | 1968 | Pan American Championship | E91 King's Indian |
| 34. W Estrada Degrandi vs I Mendivil |
| ½-½ | 17 | 1968 | Pan American Championship | C68 Ruy Lopez, Exchange |
| 35. I Mendivil vs A Morales |
| ½-½ | 22 | 1968 | Pan American Championship | E94 King's Indian, Orthodox |
| 36. H Rossetto vs I Mendivil |
| 1-0 | 57 | 1968 | Pan American Championship | E94 King's Indian, Orthodox |
| 37. I Mendivil vs J Boudy Bueno |
| ½-½ | 57 | 1968 | Pan American Championship | E61 King's Indian |
| 38. F J Perez vs I Mendivil |
| 0-1 | 38 | 1968 | Pan American Championship | E61 King's Indian |
| 39. I Mendivil vs J L Alvarez del Monte |
| ½-½ | 54 | 1968 | Pan American Championship | B73 Sicilian, Dragon, Classical |
| 40. G Pena vs I Mendivil |
| ½-½ | 14 | 1968 | Pan American Championship | E20 Nimzo-Indian |
| 41. I Mendivil vs J Diaz |
| 0-1 | 41 | 1968 | Pan American Championship | B32 Sicilian |
| 42. Letelier vs I Mendivil |
| 1-0 | 41 | 1968 | Pan American Championship | E92 King's Indian |
| 43. E Cobo Arteaga vs I Mendivil |
| 1-0 | 22 | 1968 | Pan American Championship | B88 Sicilian, Fischer-Sozin Attack |
| 44. E Jimenez Zerquera vs I Mendivil |
| 1-0 | 36 | 1968 | Pan American Championship | E87 King's Indian, Samisch, Orthodox |
| 45. I Mendivil vs J R Martinez |
| ½-½ | 16 | 1968 | Pan American Championship | C50 Giuoco Piano |
| 46. E Macskasy vs I Mendivil |
| 1-0 | 58 | 1968 | Pan American Championship | E46 Nimzo-Indian |
| 47. I Mendivil vs W Ader Hausman |
| 0-1 | 25 | 1968 | Pan American Championship | D10 Queen's Gambit Declined Slav |
| 48. S Garcia Martinez vs I Mendivil |
| 1-0 | 26 | 1968 | Pan American Championship | B09 Pirc, Austrian Attack |
| 49. I Mendivil vs O Yepez Obando |
| 0-1 | 38 | 1968 | Pan American Championship | B72 Sicilian, Dragon |
| 50. I Mendivil vs O Rodriguez Vargas |
| 0-1 | 43 | 1969 | Mar del Plata Zonal | B84 Sicilian, Scheveningen |
Kibitzing
