| 11 ago 2026 | John Veny Akkarakaran 2308 | Stefanou, Konstantinos 2262 | 1-0 | A47 Pseudo Queen's Indian Defense | 9th SKG Open 2026 | Group A | 55 | Ver |
| 10 ago 2026 | Stefanou, Konstantinos 2262 | Palaiologou, Apostolos 2201 | 1-0 | E15 Defensa India de Dama: Fianchetto Variation, Nimzowitsch Variation, Quiet Line | 9th SKG Open 2026 | Group A | 71 | Ver |
| 9 ago 2026 | Stefanou, Konstantinos 2262 | Vasiliadis, Theodoros 2039 | ½-½ | E65 Defensa India de Rey: Fianchetto Variation, Yugoslav Variation | 9th SKG Open 2026 | Group A | 65 | Ver |
| 8 ago 2026 | Stefanou, Konstantinos 2262 | Tanenbaum, Zachary 2290 | ½-½ | A80 Defensa Holandesa | 9th SKG Open 2026 | Group A | 44 | Ver |
| 8 ago 2026 | Toliopoulos, Konstantinos 2086 | Stefanou, Konstantinos 2262 | 0-1 | B27 Defensa Siciliana: Katalimov Variation | 9th SKG Open 2026 | Group A | 60 | Ver |
| 4 ago 2026 | Stefanou, Konstantinos 2262 | Odabasi, Ruzgar 2216 | 0-1 | E14 Queen's Indian Defense, with e3 | 35th Kavala Open Chess Tournament \"Vasilis Theodoridis\" | Group A | 60 | Ver |
| 10 jul 2026 | Papaioannou, Dimitrios 2348 | Stefanou, Konstantinos 2260 | ½-½ | B30 Defensa Siciliana: Nyezhmetdinov-Rossolimo Attack | 53rd Greek Team Championship 2026 | 37 | Ver |
| 10 jul 2026 | Stefanou, Konstantinos 2260 | Stefanou, Dimitrios 2358 | ½-½ | B12 Defensa Caro-Kann: Advance Variation, Short Variation | 53rd Greek Team Championship 2026 | 17 | Ver |
| 10 jul 2026 | Christodoulou, Panormitis 2098 | Stefanou, Konstantinos 2260 | ½-½ | B40 Defensa Siciliana: French Variation | 53rd Greek Team Championship 2026 | 42 | Ver |
| 8 jul 2026 | Stefanou, Konstantinos 2260 | Tagkaloglou, Savvas Stefanos 2031 | 1-0 | D37 Gambito de Dama rehusado: Three Knights Variation | 53rd Greek Team Championship 2026 | 42 | Ver |
| 7 jul 2026 | Kalogridis, Antonios 2399 | Stefanou, Konstantinos 2260 | 1-0 | D31 Gambito de Dama rehusado: Charousek Variation | 53rd Greek Team Championship 2026 | 38 | Ver |
| 23 mar 2026 | Oikonomopoulos, Filippos 2191 | Stefanou, Konstantinos 2269 | 0-1 | B23 Defensa Siciliana: Closed, Traditional | 3rd International Open Chess Tournament of Katerini Group A | 41 | Ver |
| 21 mar 2026 | Stratigos, Spiros 2123 | Stefanou, Konstantinos 2269 | 1-0 | B40 Defensa Siciliana: French Variation | 3rd International Open Chess Tournament of Katerini Group A | 43 | Ver |
| 23 feb 2026 | Stefanou, Konstantinos 2233 | Liloni, Francesco Mattia 2137 | 1-0 | E11 Defensa Bogoindia: Retreat Variation | 9th Vardaris Open 2026 | 29 | Ver |
| 22 feb 2026 | Krallis, Christos 2423 | Stefanou, Konstantinos 2233 | 1-0 | B35 Defensa Siciliana: Accelerated Dragon, Modern Bc4 Variation | 9th Vardaris Open 2026 | 54 | Ver |
| 22 feb 2026 | Papasimakopoulos, Alexandros 2363 | Stefanou, Konstantinos 2233 | 0-1 | E44 Defensa Nimzoindia: St. Petersburg Variation, Romanishin-Psakhis Variation | 9th Vardaris Open 2026 | 60 | Ver |
| 21 feb 2026 | Stefanou, Konstantinos 2233 | Valsecchi, Alessio 2439 | ½-½ | E46 Defensa Nimzoindia: Normal Variation | 9th Vardaris Open 2026 | 31 | Ver |
| 21 feb 2026 | Akat, Elifnaz 2104 | Stefanou, Konstantinos 2233 | 0-1 | B40 Defensa Siciliana: French Variation | 9th Vardaris Open 2026 | 45 | Ver |
| 20 feb 2026 | Stefanou, Konstantinos 2233 | Yordanova, Svetla 2053 | 1-0 | A06 Apertura Zukertort | 9th Vardaris Open 2026 | 55 | Ver |
| 4 ene 2026 | Stefanou, Konstantinos 2234 | Pankiv, Maksym 2296 | 0-1 | E08 Apertura Catalana: Closed | Open A | 61 | Ver |