| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 51. M Leuw vs C Costello |
| ½-½ | 54 | 1993 | Leeuwarden Open | C18 French, Winawer |
| 52. C Costello vs H Jolles |
| ½-½ | 29 | 1993 | Leeuwarden Open | A29 English, Four Knights, Kingside Fianchetto |
| 53. C Costello vs E Wiersma |
| ½-½ | 24 | 1993 | Leeuwarden Open | A10 English |
| 54. C Costello vs M Ferguson |
| 0-1 | 38 | 1994 | 18th Lloyds Bank Masters Open | A12 English with b3 |
| 55. Timoshenko vs C Costello |
| 1-0 | 34 | 1995 | Mainz op | D63 Queen's Gambit Declined, Orthodox Defense |
| 56. C Costello vs R J Dive |
| 0-1 | 27 | 1995 | 2nd Tyneside Intl Tt | A27 English, Three Knights System |
| 57. G Hassabis vs C Costello |
| ½-½ | 17 | 1995 | Hastings Centenary Masters | D00 Queen's Pawn Game |
| 58. C Costello vs Naveen Jain |
| 0-1 | 27 | 1995 | Hastings Centenary Masters | D63 Queen's Gambit Declined, Orthodox Defense |
| 59. J S Macrae vs C Costello |
| 0-1 | 28 | 1995 | Hastings Centenary Masters | D03 Torre Attack (Tartakower Variation) |
| 60. C Costello vs C Duncan |
| 0-1 | 38 | 1995 | Hastings Centenary Masters | A21 English |
| 61. J G Wilson vs C Costello |
| ½-½ | 40 | 1995 | Hastings Centenary Masters | D35 Queen's Gambit Declined |
| 62. C Costello vs D A Wood |
| 0-1 | 40 | 1995 | Hastings Centenary Masters | A25 English |
| 63. A Shah vs C Costello |
| 0-1 | 26 | 1995 | Hastings Centenary Masters | C02 French, Advance |
| 64. C Costello vs C W Kennaugh |
| 0-1 | 59 | 1995 | Hastings Centenary Masters | A21 English |
| 65. P Vianin vs C Costello |
| 1-0 | 38 | 1995 | Hastings Centenary Masters | C01 French, Exchange |
| 66. C Costello vs E Player |
| 0-1 | 46 | 1995 | Isle of Man Open | A37 English, Symmetrical |
| 67. S Ackerman vs C Costello |
| 0-1 | 52 | 1995 | Isle of Man Open | A15 English |
| 68. C Costello vs J Howell |
| 0-1 | 33 | 1995 | Isle of Man Open | A10 English |
| 69. J McLean vs C Costello |
| 1-0 | 45 | 1995 | Isle of Man Open | C02 French, Advance |
| 70. C Costello vs O R O'Siochru |
| 1-0 | 71 | 1995 | Isle of Man Open | A13 English |
| 71. N Gill vs C Costello |
| ½-½ | 38 | 1995 | Isle of Man Open | D68 Queen's Gambit Declined, Orthodox Defense, Classical |
| 72. C Costello vs J Bellin |
| ½-½ | 15 | 1995 | Isle of Man Open | A25 English |
| 73. E Martinovsky vs C Costello |
| ½-½ | 24 | 1995 | Isle of Man Open | D02 Queen's Pawn Game |
| 74. C Costello vs D G Ellison |
| 1-0 | 64 | 1995 | Isle of Man Open | A10 English |
| 75. T Straeter vs C Costello |
| 1-0 | 29 | 1996 | Hastings Challengers 1995/96 | D05 Queen's Pawn Game |
Kibitzing
