| Nov 30, 2025 | Georgiev | ½–½ | Costachi | Round 13: Georgiev, Kiril - Costachi, Mihnea | English Opening: Anglo-Indian Defense, King's Indian Formation | |
| Nov 30, 2025 | Costachi | 0–1 | Iturrizaga Bonelli | Round 12: Costachi, Mihnea - Iturrizaga Bonelli, Eduardo | Bogo-Indian Defense: Wade-Smyslov Variation | |
| Nov 30, 2025 | Pantsulaia | ½–½ | Costachi | Round 11: Pantsulaia, Levan - Costachi, Mihnea | King's Indian Attack: Symmetrical Defense | |
| Nov 30, 2025 | Costachi | 1–0 | Anton Guijarro | Round 10: Costachi, Mihnea - Anton Guijarro, David | Bogo-Indian Defense: Nimzowitsch Variation | |
| Nov 30, 2025 | Uruci | 0–1 | Costachi | Round 9: Uruci, Ardit - Costachi, Mihnea | Scotch Game: Cochrane-Shumov Defense | |
| Nov 30, 2025 | Costachi | 0–1 | Plat | Round 8: Costachi, Mihnea - Plat, Vojtech | Pirc Defense | |
| Nov 30, 2025 | Livaic | 0–1 | Costachi | Round 7: Livaic, Leon - Costachi, Mihnea | Zukertort Opening: Old Indian Attack | |
| Nov 30, 2025 | Costachi | 1–0 | Kukelko | Round 6: Costachi, Mihnea - Kukelko, Alexey | Semi-Slav Defense: Stoltz Variation, Shabalov Attack | |
| Nov 30, 2025 | Boci | 0–1 | Costachi | Round 5: Boci, Mateu - Costachi, Mihnea | Ruy Lopez: Morphy Defense, Modern Steinitz Defense | |
| Nov 30, 2025 | Costachi | 0–1 | Wojtaszek | Round 4: Costachi, Mihnea - Wojtaszek, Radoslaw | Bogo-Indian Defense: Wade-Smyslov Variation | |
| Nov 30, 2025 | Markocic | 0–1 | Costachi | Round 3: Markocic, Tine - Costachi, Mihnea | English Opening: Anglo-Indian Defense, Queen's Knight Variation | |
| Nov 30, 2025 | Costachi | 1–0 | Kuipers | Round 2: Costachi, Mihnea - Kuipers, Dustin | Queen's Gambit Declined: Janowski Variation | |
| Nov 30, 2025 | Vidikjevski | 0–1 | Costachi | Round 1: Vidikjevski, Vancho - Costachi, Mihnea | Ruy Lopez: Morphy Defense, Modern Steinitz Defense | |
| Nov 29, 2025 | Stamatiou | 1–0 | Costachi | Round 10: Stamatiou, Rodolfos - Costachi, Mihnea | King's Indian Defense: Kazakh Variation | |
| Nov 29, 2025 | Costachi | 0–1 | Santos Latasa | Round 9: Costachi, Mihnea - Santos Latasa, Jaime | Semi-Slav Defense | |
| Nov 29, 2025 | Ramaj | ½–½ | Costachi | Round 8: Ramaj, Ergit - Costachi, Mihnea | Italian Game: Giuoco Pianissimo, Normal | |
| Nov 29, 2025 | Costachi | 1–0 | Kelmendi | Round 7: Costachi, Mihnea - Kelmendi, Bajrush | Queen's Pawn Game: Modern Defense | |
| Nov 29, 2025 | Szalay-Ocsak | ½–½ | Costachi | Round 6: Szalay-Ocsak, Bank - Costachi, Mihnea | Nimzo-Larsen Attack: Classical Variation | |
| Nov 28, 2025 | Rama | ½–½ | Costachi | Round 4: Rama, Lorenc - Costachi, Mihnea | Zukertort Opening: Nimzo-Larsen Variation | |
| Nov 28, 2025 | Costachi | 0–1 | Ivanchuk | Round 3: Costachi, Mihnea - Ivanchuk, Vasyl | Queen's Indian Defense: Fianchetto Variation, Nimzowitsch Variation | |
| Jul 12, 2024 | Costachi | ½–½ | Yuffa | XLIII Open Villa de Benasque 2024 | Queen's Gambit Declined: Vienna Variation, Quiet Variation | |
| Jul 10, 2024 | Quparadze | ½–½ | Costachi | XLIII Open Villa de Benasque 2024 | Petrov's Defense: Classical Attack, Staunton Variation | |
| Jul 9, 2024 | Costachi | ½–½ | Gopal G.N. | XLIII Open Villa de Benasque 2024 | Grünfeld Defense: Exchange Variation | |
| Jun 14, 2024 | Cebotari | ½–½ | Costachi | Round 10: Cebotari, Stanislav - Costachi, Mihnea | King's Indian Attack: Wahls Defense | |
| Jun 14, 2024 | Costachi | ½–½ | Manea | Round 9: Costachi, Mihnea - Manea, Alexandru | Slav Defense: Chebanenko Variation, Advance System | |
| Jun 14, 2024 | Cosman | 0–1 | Costachi | Round 8: Cosman, Andreea-Marioara - Costachi, Mihnea | King's Indian Defense: Smyslov Variation | |
| Jun 14, 2024 | Costachi | 1–0 | Ghita | Round 7: Costachi, Mihnea - Ghita, Vlad-Bogdan | Slav Defense: Schlechter Variation | |
| Jun 14, 2024 | Sachilaru | 1–0 | Costachi | Round 6: Sachilaru, Alexandru - Costachi, Mihnea | Ruy Lopez: Morphy Defense, Modern Steinitz Defense | |
| Jun 14, 2024 | Costachi | 0–1 | Narayanan S L | Round 5: Costachi, Mihnea - Narayanan S L | Queen's Gambit Declined: Vienna Variation, Quiet Variation | |
| Jun 13, 2024 | Visanescu | 0–1 | Costachi | Round 4: Visanescu, Dragos-Nicholas - Costachi, Mihnea | Italian Game: Classical Variation, Giuoco Pianissimo, with d6 | |
| Jun 13, 2024 | Costachi | 1–0 | Maria | Round 3: Costachi, Mihnea - Maria, Lia-Alexandra | Queen's Gambit Accepted: Classical Defense, Steinitz Variation, Exchange Variation | |
| Jun 13, 2024 | Ivancescu | 0–1 | Costachi | Round 2: Ivancescu, Bogdan-Andrei - Costachi, Mihnea | Italian Game: Classical Variation, Giuoco Pianissimo, with h6 | |
| Jun 13, 2024 | Costachi | 1–0 | Stanescu | Round 1: Costachi, Mihnea - Stanescu, Andrei-Cornel | Rapport-Jobava System, with e6 | |
| Mar 24, 2024 | Filev | ½–½ | Costachi | Round 10: Filev, Georgi - Costachi, Mihnea | Ruy Lopez: Morphy Defense, Modern Steinitz Defense, Fianchetto Variation | |
| Mar 24, 2024 | Costachi | 0–1 | Ponomariov | Round 9: Costachi, Mihnea - Ponomariov, Ruslan | Queen's Gambit Declined: Barmen Variation | |
| Mar 24, 2024 | Kuzubov | 0–1 | Costachi | Round 8: Kuzubov, Yuriy - Costachi, Mihnea | East Indian Defense | |
| Mar 24, 2024 | Costachi | 1–0 | Veneteanu | Round 7: Costachi, Mihnea - Veneteanu, Mihai | Queen's Gambit Declined: Tartakower Defense, Exchange Variation | |
| Mar 24, 2024 | Deac | 1–0 | Costachi | Round 6: Deac, Bogdan-Daniel - Costachi, Mihnea | Italian Game: Classical Variation, Giuoco Pianissimo, with a6 | |
| Mar 24, 2024 | Costachi | 1–0 | Nedelcu | Round 5: Costachi, Mihnea - Nedelcu, Teodor-Cosmin | Queen's Gambit Declined: Exchange Variation, Reshevsky Variation | |
| Mar 23, 2024 | Pisu | 0–1 | Costachi | Round 4: Pisu, Robert-Daniel - Costachi, Mihnea | Indian Defense: Przepiorka Variation | |
| Mar 23, 2024 | Costachi | ½–½ | Dragomirescu | Round 3: Costachi, Mihnea - Dragomirescu, Angela | Philidor Defense: Lion Variation, Shirov Gambit | |
| Mar 23, 2024 | Andries | 0–1 | Costachi | Round 2: Andries, Alf - Costachi, Mihnea | Scotch Game: Schmidt Variation | |
| Mar 23, 2024 | Costachi | 1–0 | Stoica | Round 1: Costachi, Mihnea - Stoica, Vlad V. | Bishop's Opening: Vienna Hybrid, Spielmann Attack | |
| Dec 10, 2024 | Costachi | 0–1 | Navara | Round 2: Costachi, Mihnea - Navara, David | ? | |
| Dec 10, 2024 | Costachi | 1–0 | Dragicevic | Round 4: Costachi, Mihnea - Dragicevic, Drazen | ? | |
| Dec 10, 2024 | Costachi | ½–½ | Bulmaga | Round 6: Costachi, Mihnea - Bulmaga, Irina | ? | |
| Dec 10, 2024 | Costachi | 1–0 | Dobrikov | Round 8: Costachi, Mihnea - Dobrikov, Marco | ? | |
| Dec 10, 2024 | Costachi | 0–1 | Gatineau | Round 10: Costachi, Mihnea - Gatineau, Yovann | ? | |
| Dec 10, 2024 | Trapp | 0–1 | Costachi | Round 1: Trapp, Maximilian - Costachi, Mihnea | ? | |
| Dec 10, 2024 | Kesidis | 0–1 | Costachi | Round 3: Kesidis, Odyseas - Costachi, Mihnea | ? | |
| Dec 10, 2024 | Lagarde | 1–0 | Costachi | Round 5: Lagarde, Maxime - Costachi, Mihnea | ? | |
| Dec 10, 2024 | Muter | ½–½ | Costachi | Round 7: Muter, Donny - Costachi, Mihnea | ? | |
| Dec 10, 2024 | Ragger | 1–0 | Costachi | Round 9: Ragger, Markus - Costachi, Mihnea | ? | |
| Dec 10, 2024 | Bogoevski | 0–1 | Costachi | Round 11: Bogoevski, Jani - Costachi, Mihnea | ? | |
| Dec 9, 2024 | Costachi | 1–0 | Mueller | Round 2: Costachi, Mihnea - Mueller, Magnus | Semi-Slav Defense | |
| Dec 9, 2024 | Costachi | 1–0 | Sirigos | Round 4: Costachi, Mihnea - Sirigos, Nikolaos | Old Indian Defense: Normal Variation | |
| Dec 9, 2024 | Costachi | 0–1 | Mamedov | Round 6: Costachi, Mihnea - Mamedov, Rauf | Tarrasch Defense: Schara Gambit | |
| Dec 9, 2024 | Costachi | ½–½ | Radeva | Round 8: Costachi, Mihnea - Radeva, Viktoria | Rapport-Jobava System, with e6 | |
| Dec 9, 2024 | Costachi | 0–1 | Pultinevicius | Round 9: Costachi, Mihnea - Pultinevicius, Paulius | Semi-Slav Defense | |
| Dec 9, 2024 | Costachi | 1–0 | Zlatkov | Round 11: Costachi, Mihnea - Zlatkov, Anton | Bogo-Indian Defense: Nimzowitsch Variation | |
| Dec 9, 2024 | Costachi | 0–1 | Muradli | Round 13: Costachi, Mihnea - Muradli, Mahammad | King's Indian Defense: Averbakh Variation, Main Line | |
| Dec 9, 2024 | Marques | 0–1 | Costachi | Round 1: Marques, Ricardo Taborda Trigo - Costachi, Mihnea | King's Indian Defense: Kazakh Variation | |
| Dec 9, 2024 | Fedoseev | 1–0 | Costachi | Round 3: Fedoseev, Vladimir - Costachi, Mihnea | Italian Game: Giuoco Piano | |
| Dec 9, 2024 | Vyval | 0–1 | Costachi | Round 5: Vyval, Volodymyr - Costachi, Mihnea | Scotch Game: Schmidt Variation | |
| Dec 9, 2024 | Tsolakidou | 0–1 | Costachi | Round 7: Tsolakidou, Stavroula - Costachi, Mihnea | Petrov's Defense: Modern Attack, Center Variation | |
| Dec 9, 2024 | Avramidou | 0–1 | Costachi | Round 10: Avramidou, Anastasia - Costachi, Mihnea | Indian Defense: Anti-Grünfeld, Basman-Williams Attack | |
| Dec 9, 2024 | Djukic | 0–1 | Costachi | Round 12: Djukic, Nikola - Costachi, Mihnea | Ruy Lopez: Morphy Defense, Modern Steinitz Defense, Fianchetto Variation | |
| Dec 8, 2024 | Costachi | ½–½ | Santos Latasa | Round 8: Costachi, Mihnea - Santos Latasa, Jaime | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Dec 8, 2024 | Costachi | 1–0 | Podlesnik | Round 10: Costachi, Mihnea - Podlesnik, Bogdan | Queen's Indian Defense: Yates Variation | |
| Dec 8, 2024 | Promyshlyanskiy | 0–1 | Costachi | Round 7: Promyshlyanskiy, Vitaliy - Costachi, Mihnea | Ruy Lopez: Morphy Defense, Modern Steinitz Defense | |
| Dec 8, 2024 | Motylev | 1–0 | Costachi | Round 9: Motylev, Alexander - Costachi, Mihnea | Scotch Game: Mieses Variation | |
| Dec 8, 2024 | Deac | ½–½ | Costachi | Round 11: Deac, Bogdan-Daniel - Costachi, Mihnea | Queen's Pawn Game: London System | |
| Dec 7, 2024 | Costachi | 1–0 | Iskos | Round 4: Costachi, Mihnea - Iskos, Alexandros | Queen's Gambit Declined: Three Knights Variation | |
| Dec 7, 2024 | Costachi | 0–1 | Quparadze | Round 6: Costachi, Mihnea - Quparadze, Giga | Van Geet Opening | |
| Dec 7, 2024 | Korobov | 1–0 | Costachi | Round 3: Korobov, Anton - Costachi, Mihnea | King's Indian Defense: Averbakh Variation, Modern Defense | |
| Dec 7, 2024 | Yuste Valenzuela | 0–1 | Costachi | Round 5: Yuste Valenzuela, Alejandro - Costachi, Mihnea | Italian Game: Giuoco Pianissimo, Italian Four Knights Variation | |
| Oct 5, 2024 | Maximov | 0–1 | Costachi | Round 8: Maximov, Oleg - Costachi, Mihnea | Four Knights Game: Scotch Variation Accepted | |
| Oct 3, 2024 | Dodoi | ½–½ | Costachi | Round 6: Dodoi, Matei-Teodor - Costachi, Mihnea | King's Indian Defense: Fianchetto Variation, Classical Main Line | |
| Oct 1, 2024 | Costachi | ½–½ | Patrascu | Round 4: Costachi, Mihnea - Patrascu, Catalin-Lucian | Bogo-Indian Defense: Retreat Variation | |
| Sep 28, 2024 | Padurariu | ½–½ | Costachi | Round 1: Padurariu, Mihai-Edward - Costachi, Mihnea | Italian Game: Giuoco Pianissimo, Italian Four Knights Variation | |
| Aug 4, 2024 | Costachi | 1–0 | Maksimovic | Round 5: Costachi, Mihnea - Maksimovic, Masa | Rapport-Jobava System | |
| Aug 4, 2024 | Costachi | ½–½ | Krysa | Round 7: Costachi, Mihnea - Krysa, Leandro | Rapport-Jobava System | |
| Aug 4, 2024 | Costachi | 0–1 | Sachilaru | Round 10: Costachi, Mihnea - Sachilaru, Alexandru | King's Indian Defense: Averbakh Variation, Main Line | |
| Aug 4, 2024 | Sandu | 0–1 | Costachi | Round 6: Sandu, Mihaela - Costachi, Mihnea | Ruy Lopez: Morphy Defense, Modern Steinitz Defense | |
| Aug 4, 2024 | Pranesh M | ½–½ | Costachi | Round 8: Pranesh M - Costachi, Mihnea | Italian Game: Classical Variation, Center Attack | |
| Aug 4, 2024 | Deac | 1–0 | Costachi | Round 9: Deac, Bogdan-Daniel - Costachi, Mihnea | Petrov's Defense: Millennium Attack | |
| Aug 3, 2024 | Gavrilescu | 1–0 | Costachi | Round 4: Gavrilescu, David - Costachi, Mihnea | Petrov's Defense: Modern Attack | |
| Dec 16, 2023 | Costachi | ½–½ | Sarana | European Blitz Championship | Queen's Gambit Declined: Barmen Variation | |
| Dec 16, 2023 | Costachi | 1–0 | Dragicevic | European Blitz Championship | Semi-Slav Defense: Stoltz Variation, Shabalov Attack | |
| Dec 16, 2023 | Costachi | 1–0 | Maier | European Blitz Championship | King's Indian Defense: Averbakh Variation, Flexible Defense | |
| Dec 16, 2023 | Costachi | 1–0 | Radenic | European Blitz Championship | Queen's Indian Defense: Fianchetto Variation, Kramnik Variation | |
| Dec 16, 2023 | Costachi | ½–½ | Spalir | European Blitz Championship | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Dec 16, 2023 | Vojak | 0–1 | Costachi | European Blitz Championship | Ruy Lopez: Morphy Defense, Modern Steinitz Defense | |
| Dec 16, 2023 | Herega | ½–½ | Costachi | European Blitz Championship | King's Indian Defense: Fianchetto Variation, Lesser Simagin (Spassky) | |
| Dec 16, 2023 | Navara | 1–0 | Costachi | European Blitz Championship | Slav Defense | |
| Dec 16, 2023 | Goroshkov | ½–½ | Costachi | European Blitz Championship | Zukertort Opening: Nimzo-Larsen Variation | |
| Dec 16, 2023 | Fressinet | 1–0 | Costachi | European Blitz Championship | Indian Defense: Przepiorka Variation | |
| Dec 16, 2023 | Kahleys | ½–½ | Costachi | European Blitz Championship | King's Indian Defense: Fianchetto Variation, Lesser Simagin (Spassky) | |
| Dec 15, 2023 | Costachi | ½–½ | Hulka | European Rapid Championship | Queen's Gambit Declined: Semi-Tarrasch Defense | |
| Dec 15, 2023 | Costachi | ½–½ | Vyval | European Rapid Championship | Queen's Gambit Declined: Semi-Tarrasch Defense, Exchange Variation | |