| Apr 3, 2026 | Gaertner | 1–0 | Huels | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | Zukertort Opening: Dutch Variation | |
| Mar 28, 2026 | Gaertner | 1–0 | Oita-Dragota | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | Zukertort Opening: Pirc Invitation | |
| Mar 27, 2026 | Nguyen | ½–½ | Gaertner | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | Caro-Kann Defense: Main Line | |
| Mar 27, 2026 | Gaertner | ½–½ | Burnus | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | Zukertort Opening | |
| Mar 27, 2026 | Beckmann | * | Gaertner | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | Caro-Kann Defense: Maróczy Variation | |
| Mar 27, 2026 | Gaertner | 1–0 | Direk | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | Zukertort Opening | |
| Mar 27, 2026 | Oelschlaeger | 0–1 | Gaertner | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | Zukertort Opening: Nimzo-Larsen Variation | |
| Mar 27, 2026 | Gaertner | 1–0 | Alali | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | English Opening: Symmetrical Variation | |
| Mar 27, 2026 | Moeller | 0–1 | Gaertner | Landesjugendeinzelmeisterschaft in Niedersachsen U18 | Queen's Pawn Game: Chigorin Variation, Irish Gambit | |
| Jan 5, 2025 | Gaertner | 1–0 | Drygala | Round 7: Gaertner, Alessandro - Drygala, Lars | Queen's Indian Defense: Classical Variation, Traditional Variation | |
| Jan 4, 2025 | Sreyas Payyappat | ½–½ | Gaertner | Round 5: Sreyas Payyappat - Gaertner, Alessandro | Caro-Kann Defense: Panov Attack, Modern Defense | |
| Jan 4, 2025 | Wilmink | ½–½ | Gaertner | Round 6: Wilmink, Anna - Gaertner, Alessandro | Caro-Kann Defense: Tartakower Variation | |
| Jan 3, 2025 | Gaertner | 0–1 | Schiller | Round 3: Gaertner, Alessandro - Schiller, Jan-Hendrik | English Opening: Agincourt Defense | |
| Jan 3, 2025 | Gaertner | 1–0 | Celik | Round 4: Gaertner, Alessandro - Celik, Abdullah | English Opening: King's English Variation, Kramnik-Shirov Counterattack | |
| Jan 2, 2025 | Gaertner | 0–1 | Polster | Round 1: Gaertner, Alessandro - Polster, Christian | Zukertort Opening | |
| Jan 2, 2025 | Meiwes | 1–0 | Gaertner | Round 2: Meiwes, Thore - Gaertner, Alessandro | King's Indian Defense: Orthodox Variation, Classical System | |
| Jan 7, 2023 | Gaertner | * | Wander | Lower Saxony Championship | B | Queen's Gambit Declined: Harrwitz Attack, Two Knights Defense | |
| Jan 7, 2023 | Busse | 0–1 | Gaertner | Lower Saxony Championship | B | Caro-Kann Defense: Advance Variation, Botvinnik-Carls Defense | |
| Jan 5, 2023 | Gaertner | ½–½ | Aden | Lower Saxony Championship | B | English Opening: Anglo-Indian Defense | |
