| Nov 30, 2025 | Gkadakis | 0–1 | Kostoglou | Round 6: Gkadakis, Nikolaos - Kostoglou, Apostolos | King's Indian Defense: Kramer Variation | |
| Nov 29, 2025 | Kostoglou | 1–0 | Tamiolakis | Round 5: Kostoglou, Apostolos - Tamiolakis, Grigorios | French Defense: Tarrasch Variation, Open System, Euwe-Keres Line | |
| Nov 29, 2025 | Megagiannis | 0–1 | Kostoglou | Round 4: Megagiannis, Maximos - Kostoglou, Apostolos | French Defense: McCutcheon Variation, Lasker Variation | |
| Nov 28, 2025 | Kreonas | 0–1 | Kostoglou | Round 3: Kreonas, Dimitrios - Kostoglou, Apostolos | King's Indian Defense: Smyslov Variation | |
| Nov 28, 2025 | Kostoglou | 1–0 | Afantiti | Round 2: Kostoglou, Apostolos - Afantiti, Maria Varvara | Caro-Kann Defense: Tartakower Variation | |
| Nov 27, 2025 | Angelakis | 0–1 | Kostoglou | Round 1: Angelakis, Emmanouil - Kostoglou, Apostolos | East Indian Defense | |
| Jul 12, 2025 | Danezis | ½–½ | Kostoglou | Round 9: Danezis, Prodromos - Kostoglou, Apostolos | Pirc Defense: Classical Variation, Quiet System | |
| Jul 10, 2025 | Kostoglou | ½–½ | Tamiolakis | Round 7: Kostoglou, Apostolos - Tamiolakis, Grigorios | Sicilian Defense: Kan Variation, Maróczy Bind, Réti Variation | |
| Jul 6, 2025 | Karantoniou | 0–1 | Kostoglou | Round 1: Karantoniou, Stylianos - Kostoglou, Apostolos | King's Indian Defense: Semi-Averbakh System | |
| Jul 4, 2025 | Kalonomos | ½–½ | Kostoglou | Round 7: Kalonomos, Ioannis - Kostoglou, Apostolos | English Opening: Anglo-Indian Defense, King's Indian Formation | |
| Jul 3, 2025 | Kostoglou | 0–1 | Volani | Round 3: Kostoglou, Apostolos - Volani, Olga | Sicilian Defense: Taimanov Variation | |
| Jul 3, 2025 | Kazakis | 1–0 | Kostoglou | Round 2: Kazakis, Mattheos Konstantinos - Kostoglou, Apostolos | French Defense: Tarrasch Variation, Modern System | |
| Jul 3, 2025 | Alexandrakis | 1–0 | Kostoglou | Round 5: Alexandrakis, Venizelos - Kostoglou, Apostolos | French Defense: Tarrasch Variation, Modern System | |
| Aug 31, 2024 | Kostoglou | 0–1 | Papanikolaou | Round 1: Kostoglou, Apostolos - Papanikolaou, Dimitrios Nik | Caro-Kann Defense: Tartakower Variation | |
