| Jun 7, 2026 | Kostak | ½–½ | Roessler | Round 5: Kostak, Tetyana - Roessler, Ulrike | Sicilian Defense: Delayed Alapin Variation, with d6 | |
| Jun 6, 2026 | Koehler | ½–½ | Kostak | Round 4: Koehler, Inken - Kostak, Tetyana | Pirc Defense | |
| Jun 5, 2026 | Zhang | 0–1 | Kostak | Round 3: Zhang, Fan - Kostak, Tetyana | Queen's Pawn Game | |
| Jun 5, 2026 | Kostak | ½–½ | Nguyen | Round 2: Kostak, Tetyana - Nguyen, Ha Thanh | Sicilian Defense: French Variation | |
| Jun 4, 2026 | Kostak | 0–1 | Arnhold | Round 1: Kostak, Tetyana - Arnhold, Steffi | Sicilian Defense: French Variation | |
| May 23, 2025 | Schulze | 1–0 | Kostak | Round 9: Schulze, Lara - Kostak, Tetyana | Nimzowitsch Defense: Williams Variation | |
| May 22, 2025 | Kostak | 0–1 | Heinemann | Round 8: Kostak, Tetyana - Heinemann, Josefine | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack, Fianchetto Variation | |
| May 20, 2025 | Klek | 1–0 | Kostak | Round 6: Klek, Hanna Marie - Kostak, Tetyana | Philidor Defense: Lion Variation | |
| May 19, 2025 | Kostak | 0–1 | Dolzhykova | Round 5: Kostak, Tetyana - Dolzhykova, Kateryna | French Defense: King's Indian Attack | |
| May 18, 2025 | Sickmann | 1–0 | Kostak | Round 4: Sickmann, Lisa - Kostak, Tetyana | Philidor Defense: Lion Variation, Shirov Gambit | |
| May 17, 2025 | Kostak | 1–0 | Peglau | Round 3: Kostak, Tetyana - Peglau, Charis | Modern Defense: Pseudo-Austrian Attack | |
| May 16, 2025 | Wagner | 1–0 | Kostak | Round 2: Wagner, Dinara - Kostak, Tetyana | Nimzo-Indian Defense: Normal Variation | |
| May 15, 2025 | Kostak | ½–½ | Schneider | Round 1: Kostak, Tetyana - Schneider, Jana | Queen's Pawn Game: Colle System | |
| May 14, 2025 | Kostak | ½–½ | Sieber | Round 7: Kostak, Tetyana - Sieber, Fiona | Sicilian Defense: Old Sicilian | |
| Apr 17, 2025 | Nemec | 1–0 | Kostak | Round 1: Nemec, Jachym - Kostak, Tetyana | Zukertort Opening | |
| Jan 4, 2025 | Kostak | 0–1 | Velicka | 35. Staufer Open 2025 | Caro-Kann Defense: Breyer Variation | |
| Jan 2, 2025 | Kostak | 0–1 | Meissner | 35. Staufer Open 2025 | Sicilian Defense: Delayed Alapin Variation, with d6 | |
| Sep 28, 2024 | Kostak | 1–0 | Margaryan | Round 20: Kostak, Tetyana - Margaryan, Susanna | Sicilian Defense: Wing Gambit | |
| Sep 28, 2024 | Pfau | 1–0 | Kostak | Round 16: Pfau, Beate - Kostak, Tetyana | English Opening: King's English Variation | |
| Sep 28, 2024 | Heil | 0–1 | Kostak | Round 14: Heil, Marina - Kostak, Tetyana | Trompowsky Attack | |
| Sep 28, 2024 | Kostak | 1–0 | Zell | Round 1: Kostak, Tetyana - Zell, Mirjam | King's Pawn Game: Mengarini's Opening | |
| Sep 28, 2024 | Kostak | 0–1 | Dolzhykova | Round 18: Kostak, Tetyana - Dolzhykova, Kateryna | King's Indian Attack: Sicilian Variation | |
| Aug 21, 2024 | Foltin | 0–1 | Kostak | Round 4: Foltin, Alica - Kostak, Tetyana | Mexican Defense | |
| Aug 20, 2024 | Kostak | 1–0 | Wagenschuetz | Round 3: Kostak, Tetyana - Wagenschuetz, Evelyn | Sicilian Defense: Modern Variations | |
| Aug 19, 2024 | Novikova | * | Kostak | Round 1: Novikova, Margarita - Kostak, Tetyana | ? | |
| Aug 16, 2024 | Wilmink | ½–½ | Kostak | Round 9: Wilmink, Anna - Kostak, Tetyana | Philidor Defense: Lion Variation | |
| Aug 16, 2024 | Staerk | 0–1 | Kostak | Round 8: Staerk, Elisa - Kostak, Tetyana | Indian Defense: Anti-Nimzo-Indian | |
| Aug 16, 2024 | Kostak | 1–0 | Bluebaum | Round 7: Kostak, Tetyana - Bluebaum, Johanna | Queen's Pawn Game: Colle System | |
| Aug 16, 2024 | Miljkovic | 0–1 | Kostak | Round 6: Miljkovic, Jovana - Kostak, Tetyana | Old Indian Defense: Normal Variation | |
| Aug 16, 2024 | Kostak | 1–0 | Braun | Round 5: Kostak, Tetyana - Braun, Kristin | Sicilian Defense: Old Sicilian | |
| Aug 16, 2024 | Novikova | 1–0 | Kostak | Round 2: Novikova, Margarita - Kostak, Tetyana | Philidor Defense: Lion Variation | |
| Aug 16, 2024 | Kostak | 1–0 | Just | Round 1: Kostak, Tetyana - Just, Anita, Dr. | French Defense: King's Indian Attack | |
| Oct 13, 2024 | Kostak | 0–1 | Klek | Round 7: Kostak, Tetyana - Klek, Hanna Marie | Ponziani Opening: Jaenisch Counterattack | |
| Oct 13, 2024 | Kostak | 0–1 | Zhou | Round 9: Kostak, Tetyana - Zhou, Lepu Coco | Sicilian Defense: French Variation | |
| Oct 13, 2024 | Dolzhykova | 0–1 | Kostak | Round 6: Dolzhykova, Kateryna - Kostak, Tetyana | Elephant Gambit: Paulsen Countergambit | |
| Oct 13, 2024 | Stangl | 0–1 | Kostak | Round 8: Stangl, Anita, Dr. - Kostak, Tetyana | Pirc Defense | |
| Oct 12, 2024 | Kostak | 1–0 | Schulze | Round 5: Kostak, Tetyana - Schulze, Lara | Zukertort Opening: Old Indian Attack | |
| Oct 12, 2024 | Miljkovic | 0–1 | Kostak | Round 4: Miljkovic, Jovana - Kostak, Tetyana | Old Indian Defense: Normal Variation | |
| Jun 11, 2023 | Kostak | ½–½ | Zozulia | German Women's State Team Championship | Modern Defense | |
| Jun 10, 2023 | Braun | 1–0 | Kostak | German Women's State Team Championship | Sicilian Defense: Dragon Variation, Yugoslav Attack, Panov Variation | |
| Jun 9, 2023 | Kostak | 0–1 | Barpiyeva | German Women's State Team Championship | Sicilian Defense: French Variation | |
| Jun 9, 2023 | Braeutigam | 0–1 | Kostak | German Women's State Team Championship | Nimzowitsch Defense: Scandinavian Variation, Advance Variation | |
| Jun 8, 2023 | Kostak | 1–0 | Bazzazi | German Women's State Team Championship | Italian Game: Deutz Gambit | |
| — | Kostak | 1–0 | Just | Runde 2: Kostak, Tetyana - Just, Anita, Dr. | French Defense: King's Indian Attack | |
| — | Kostak | 1–0 | Wang | Runde 4: Kostak, Tetyana - Wang, Enya Marie | Queen's Pawn Game: Colle System | |
| — | Kostak | ½–½ | Neumann | Runde 6: Kostak, Tetyana - Neumann, Helena | Zukertort Opening | |
| — | Kostak | 1–0 | Koldunov | Runde 9: Kostak, Tetyana - Koldunov, Elena | Sicilian Defense: Delayed Alapin Variation, with d6 | |
| — | Kostak | 1–0 | Bruehl | Runde 3: Kostak, Tetyana - Bruehl, Katharina | Scandinavian Defense | |
| — | Kostak | 1–0 | Novikova | Runde 5: Kostak, Tetyana - Novikova, Marharyta | Rubinstein Opening | |
| — | Kostak | 1–0 | Zimmer | Runde 1: Kostak, Tetyana - Zimmer, Elke | ? | |
| — | Kostak | 0–1 | Neumann | Runde 7: Kostak, Tetyana - Neumann, Helena | Caro-Kann Defense: Breyer Variation | |
| — | Kostak | 1–0 | Trunz | Runde 9: Kostak, Tetyana - Trunz, Tamila | Sicilian Defense: French Variation | |
| — | Lukas | 0–1 | Kostak | Runde 1: Lukas, Olivia - Kostak, Tetyana | Nimzowitsch Defense: Scandinavian Variation, Advance Variation | |
| — | Babiy | 1–0 | Kostak | Runde 3: Babiy, Olga - Kostak, Tetyana | Nimzowitsch Defense: Williams Variation | |
| — | Bursan | 1–0 | Kostak | Runde 5: Bursan, Ana-Maria - Kostak, Tetyana | Polish Opening: Czech Defense | |
| — | Haug | 1–0 | Kostak | Runde 7: Haug, Mara - Kostak, Tetyana | Nimzowitsch Defense: Williams Variation | |
| — | Krasenkowa | 1–0 | Kostak | Runde 8: Krasenkowa, Elena - Kostak, Tetyana | Old Indian Defense: Ukrainian Variation | |
| — | Trunz | 1–0 | Kostak | Runde 2: Trunz, Michelle - Kostak, Tetyana | Bogo-Indian Defense: Nimzowitsch Variation | |
| — | Bursan | 1–0 | Kostak | Runde 4: Bursan, Ana-Maria - Kostak, Tetyana | Hungarian Opening | |
| — | Zschischang | 1–0 | Kostak | Runde 6: Zschischang, Marine - Kostak, Tetyana | Mikenas Defense | |
| — | Germann | 0–1 | Kostak | Runde 8: Germann, Heike - Kostak, Tetyana | Nimzo-Indian Defense: Reshevsky Variation | |