| Apr 20, 2026 | Matthaiou | 1–0 | Gkikas | Round 8: Matthaiou, Theodoros - Gkikas, Nektarios | Sicilian Defense: Moscow Variation, Main Line | |
| Apr 20, 2026 | Patrinos | ½–½ | Matthaiou | Round 9: Patrinos, Ektor - Matthaiou, Theodoros | Sicilian Defense: Najdorf Variation, Lipnitsky Attack | |
| Apr 18, 2026 | Ntrekis | 1–0 | Matthaiou | Round 6: Ntrekis, Minas - Matthaiou, Theodoros | Italian Game: Classical Variation, Giuoco Pianissimo | |
| Apr 17, 2026 | Asvestopoulos | 1–0 | Matthaiou | Round 4: Asvestopoulos, Sergios - Matthaiou, Theodoros | Ruy Lopez: Closed | |
| Apr 17, 2026 | Matthaiou | ½–½ | Sellis | Round 5: Matthaiou, Theodoros - Sellis, Charalampos | Sicilian Defense: Hyperaccelerated Dragon | |
| Apr 15, 2026 | Theodoridis | 1–0 | Matthaiou | Round 2: Theodoridis, Charalampos - Matthaiou, Theodoros | English Opening: Anglo-Indian Defense | |
| Apr 15, 2026 | Matthaiou | 0–1 | Giakamozis | Round 3: Matthaiou, Theodoros - Giakamozis, Apostolos | French Defense: Exchange Variation | |
| Mar 23, 2026 | Bahar-Mosse | 0–1 | Matthaiou | 3rd International Open Chess Tournament of Katerini Group B | King's Indian Attack: Symmetrical Defense | |
| Apr 27, 2025 | Matthaiou | * | Zarakotas | Round 7: Matthaiou, Theodoros - Zarakotas, Timoleon Rafail | ? | |
| Apr 26, 2025 | Pitsinos | * | Matthaiou | Round 6: Pitsinos, Evangelos - Matthaiou, Theodoros | ? | |
| Apr 25, 2025 | Diamantidis | * | Matthaiou | Round 5: Diamantidis, Stamatios - Matthaiou, Theodoros | Caro-Kann Defense | |
| Apr 24, 2025 | Matthaiou | 1–0 | Galerakis | Round 4: Matthaiou, Theodoros - Galerakis, Panagiotis Spyridon | Caro-Kann Defense: Exchange Variation | |
| Apr 23, 2025 | Latifis | 1–0 | Matthaiou | Round 2: Latifis, Panagiotis - Matthaiou, Theodoros | Benoni Defense: Benoni-Indian Defense, Kingside Move Order | |
| Jun 28, 2024 | Matthaiou | * | Kouroupakis | Round 9: Matthaiou, Theodoros - Kouroupakis, Odysseas | ? | |
| Jun 27, 2024 | Matthaiou | * | Linaras | Round 8: Matthaiou, Theodoros - Linaras, Dimitrios | ? | |
| Jun 26, 2024 | Nikolakopoulos | 1–0 | Matthaiou | Round 7: Nikolakopoulos, Leonidas Marios - Matthaiou, Theodoros | Sicilian Defense: O'Kelly Variation, Normal System | |
| Jun 25, 2024 | Matthaiou | * | Estiadis | Round 6: Matthaiou, Theodoros - Estiadis, Georgios | ? | |
| Jun 25, 2024 | Papadimopoulos | * | Matthaiou | Round 5: Papadimopoulos, Fragkiskos - Matthaiou, Theodoros | ? | |
| Jun 24, 2024 | Nikolakopoulos | * | Matthaiou | Round 4: Nikolakopoulos, Vasileios - Matthaiou, Theodoros | ? | |
| Jun 23, 2024 | Matthaiou | * | Patrinos | Round 3: Matthaiou, Theodoros - Patrinos, Ektor | ? | |
| Jun 23, 2024 | Kartsakis | * | Matthaiou | Round 2: Kartsakis, Ioannis - Matthaiou, Theodoros | ? | |
| May 7, 2024 | Lafkidis | 1–0 | Matthaiou | Round 1: Lafkidis, Apostolos - Matthaiou, Theodoros | English Opening: Anglo-Indian Defense | |
