| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. A S Segal vs H MacGrillen |
| 1-0 | 47 | 1969 | World Student Team Championship qual-1 | E10 Queen's Pawn Game |
| 27. H MacGrillen vs G Sigurjonsson |
| ½-½ | 47 | 1969 | World Student Team Championship qual-1 | E92 King's Indian |
| 28. N Kazilaris vs H MacGrillen |
| ½-½ | 41 | 1969 | World Student Team Championship qual-1 | D16 Queen's Gambit Declined Slav |
| 29. H MacGrillen vs Tukmakov |
 | 0-1 | 32 | 1969 | World Student Team Championship qual-1 | A27 English, Three Knights System |
| 30. H MacGrillen vs K Teboudi |
| ½-½ | 47 | 1969 | World Student Team Championship Final-C | A27 English, Three Knights System |
| 31. P Mertens vs H MacGrillen |
| 0-1 | 39 | 1969 | World Student Team Championship Final-C | E92 King's Indian |
| 32. H MacGrillen vs C Pritchett |
| ½-½ | 41 | 1969 | World Student Team Championship Final-C | E56 Nimzo-Indian, 4.e3, Main line with 7...Nc6 |
| 33. M Benoit vs H MacGrillen |
| 0-1 | 53 | 1969 | World Student Team Championship Final-C | C26 Vienna |
| 34. Ray Byrne vs H MacGrillen |
| 0-1 | 36 | 1971 | Cork op | E92 King's Indian |
| 35. A Coldrick vs H MacGrillen |
| ½-½ | 27 | 1971 | Cork op | B93 Sicilian, Najdorf, 6.f4 |
| 36. J Moles vs H MacGrillen |
| 1-0 | 19 | 1971 | Cork op | B47 Sicilian, Taimanov (Bastrikov) Variation |
| 37. H MacGrillen vs G McCurdy |
| 1-0 | 49 | 1971 | Cork op | A73 Benoni, Classical, 9.O-O |
| 38. H MacGrillen vs P G Henry |
| ½-½ | 59 | 1971 | Cork op | D37 Queen's Gambit Declined |
| 39. Y Kraidman vs H MacGrillen |
| 1-0 | 32 | 1972 | Skopje Olympiad qual-5 | E41 Nimzo-Indian |
| 40. H MacGrillen vs J Diez del Corral |
| ½-½ | 47 | 1972 | Skopje Olympiad qual-5 | A31 English, Symmetrical, Benoni Formation |
| 41. H MacGrillen vs S Krstic |
| ½-½ | 21 | 1972 | Skopje Olympiad qual-5 | E92 King's Indian |
| 42. J Durao vs H MacGrillen |
| 1-0 | 18 | 1972 | Skopje Olympiad qual-5 | B06 Robatsch |
| 43. Myagmarsuren vs H MacGrillen |
 | 1-0 | 57 | 1972 | Skopje Olympiad qual-5 | B08 Pirc, Classical |
| 44. H MacGrillen vs Jansa |
| 0-1 | 59 | 1972 | Skopje Olympiad qual-5 | A21 English |
| 45. B Kchouk vs H MacGrillen |
| 0-1 | 40 | 1972 | Skopje Olympiad Final-C | E41 Nimzo-Indian |
| 46. H MacGrillen vs M Campos Lopez |
| ½-½ | 37 | 1972 | Skopje Olympiad Final-C | E75 King's Indian, Averbakh, Main line |
| 47. H MacGrillen vs R Chavez Chavez |
| 1-0 | 39 | 1972 | Skopje Olympiad Final-C | E42 Nimzo-Indian, 4.e3 c5, 5.Ne2 (Rubinstein) |
| 48. S J Hutchings vs H MacGrillen |
| ½-½ | 40 | 1972 | Skopje Olympiad Final-C | A25 English |
| 49. H MacGrillen vs T Hay |
| ½-½ | 58 | 1972 | Skopje Olympiad Final-C | E73 King's Indian |
| 50. H MacGrillen vs E Gonzales |
| ½-½ | 28 | 1972 | Skopje Olympiad Final-C | D25 Queen's Gambit Accepted |
Kibitzing
