| Mar 2, 2025 | Kosta | 0–1 | Kazantzoglou | Round 6: Kosta, Kelvin - Kazantzoglou, Stefanos | Vienna Game: Mieses Variation | |
| Mar 2, 2025 | Trimitzios | 1–0 | Kosta | Round 5: Trimitzios, Petros - Kosta, Kelvin | Zukertort Opening: Nimzo-Larsen Variation | |
| Oct 25, 2024 | Christodoulou | 1–0 | Kosta | 39th European Chess Club Cup | Caro-Kann Defense: Maróczy Variation | |
| Oct 24, 2024 | Kosta | ½–½ | Paasikangas | 39th European Chess Club Cup | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack, Fianchetto Variation | |
| Oct 23, 2024 | Braeutigam | ½–½ | Kosta | 39th European Chess Club Cup | English Opening: King's English Variation, Three Knights System | |
| Oct 22, 2024 | Kosta | 0–1 | Gulbas | 39th European Chess Club Cup | Modern Defense: Geller's System | |
| Oct 21, 2024 | Gryshko | 1–0 | Kosta | 39th European Chess Club Cup | Caro-Kann Defense: Advance Variation, Botvinnik-Carls Defense | |
| Oct 20, 2024 | Kosta | ½–½ | Sos Andreu | 39th European Chess Club Cup | Caro-Kann Defense: Two Knights Attack | |
| Nov 13, 2023 | Bacojo | 1–0 | Kosta | FIDEWORLDYOUTHCHESSCHAMPIONSHIP Open 18 | Bogo-Indian Defense: Grünfeld Variation | |
| Aug 11, 2021 | Kosta | 1–0 | Prata | World Youth Cup 2021 O14-G14 - Open 14 | Caro-Kann Defense: Classical Variation, Seirawan Variation | |
| Aug 11, 2021 | Kosta | 1–0 | Ramaj | World Youth Cup 2021 O14-G14 - Open 14 | Scandinavian Defense: Mieses-Kotroc Variation | |
| Aug 11, 2021 | Kosta | 0–1 | Masilo | World Youth Cup 2021 O14-G14 - Open 14 | Sicilian Defense: Moscow Variation, Main Line | |
| Aug 11, 2021 | Kosta | 1–0 | Willder | World Youth Cup 2021 O14-G14 - Open 14 | Four Knights Game: Italian Variation | |
| Aug 11, 2021 | Kosta | 0–1 | De Carvalho | World Youth Cup 2021 O14-G14 - Open 14 | Sicilian Defense: Closed | |
| Aug 11, 2021 | Chouhan | 1–0 | Kosta | World Youth Cup 2021 O14-G14 - Open 14 | Indian Defense | |
| Aug 11, 2021 | Arias Diaz | 1–0 | Kosta | World Youth Cup 2021 O14-G14 - Open 14 | Queen's Gambit Declined: Exchange Variation, Reshevsky Variation | |
| Aug 11, 2021 | Brady | 0–1 | Kosta | World Youth Cup 2021 O14-G14 - Open 14 | English Opening: Neo-Catalan | |
| Aug 11, 2021 | Abris | 1–0 | Kosta | World Youth Cup 2021 O14-G14 - Open 14 | Czech Defense | |
