| Jun 20, 2026 | Thorfinnsson | ½–½ | Hjartarson | Green Diamond - Final Four | English Opening: King's English Variation, Four Knights Variation, Fianchetto Line, with Nb6 | |
| Jun 20, 2026 | Hjartarson | 0–1 | Thorfinnsson | Green Diamond - Final Four | English Opening: Symmetrical Variation, Ultra-Symmetrical Variation | |
| Jun 20, 2026 | Thorfinnsson | 0–1 | Hjartarson | Green Diamond - Final Four | Torre Attack: Fianchetto Defense | |
| Jun 20, 2026 | Hjartarson | ½–½ | Johannsson | Green Diamond Invitational 2026 | King's Pawn Game | |
| Jun 20, 2026 | Heimisson | ½–½ | Hjartarson | Green Diamond Invitational 2026 | King's Indian Attack: Spassky Variation | |
| Jun 20, 2026 | Hjartarson | 1–0 | Olafsson | Green Diamond Invitational 2026 | Sicilian Defense: Najdorf Variation, Opocensky Variation | |
| Jun 20, 2026 | Thorfinnsson | 0–1 | Hjartarson | Green Diamond Invitational 2026 | King's Indian Defense: Orthodox Variation, Bayonet Attack | |
| Jun 20, 2026 | Hjartarson | 1–0 | Stefansson | Green Diamond Invitational 2026 | Sicilian Defense: Kan Variation, Polugaevsky Variation | |
| Jun 20, 2026 | Hjartarson | 0–1 | Thorfinnsson | Green Diamond Invitational 2026 | Italian Game: Two Knights Defense, Modern Bishop's Opening | |
| Jun 20, 2026 | Ulfarsson | 0–1 | Hjartarson | Green Diamond Invitational 2026 | Alekhine Defense: Normal Variation | |
| Jun 19, 2026 | Hjartarson | 0–1 | Stefansson | Green Diamond - Final Four | Sicilian Defense: Nimzowitsch Variation, Advance Variation | |
| Jun 19, 2026 | Stefansson | 1–0 | Hjartarson | Green Diamond - Final Four | Queen's Indian Defense: Fianchetto Variation, Nimzowitsch Variation | |
| Jun 19, 2026 | Gretarsson | 1–0 | Hjartarson | Green Diamond Invitational 2026 | King's Indian Defense: Orthodox Variation | |
| Jun 19, 2026 | Stefansson | 1–0 | Hjartarson | Green Diamond Invitational 2026 | Bogo-Indian Defense: Vitolins Variation | |
| Jun 10, 2026 | Mannion | 0–1 | Hjartarson | Round 9: Mannion, Stephen R - Hjartarson, Johann | Pirc Defense: Austrian Attack, Weiss Variation | |
| Jun 9, 2026 | Hjartarson | 0–1 | Danielsen | Round 8: Hjartarson, Johann - Danielsen, Henrik | Queen's Indian Defense: Anti-Queen's Indian System | |
| Jun 7, 2026 | Hjartarson | 1–0 | Berend | Round 6: Hjartarson, Johann - Berend, Fred | Sicilian Defense: Taimanov Variation, Bastrikov Variation, English Attack | |
| Jun 6, 2026 | Sielecki | ½–½ | Hjartarson | Round 5: Sielecki, Christof - Hjartarson, Johann | King's Indian Defense: Orthodox Variation, Aronin-Taimanov Defense | |
| Jun 5, 2026 | Hjartarson | 1–0 | Rahal Vives | Round 4: Hjartarson, Johann - Rahal Vives, Michael Anthony | Kangaroo Defense | |
| Jun 4, 2026 | Di Fonzo | 0–1 | Hjartarson | Round 3: Di Fonzo, Valerio - Hjartarson, Johann | Sicilian Defense: French Variation | |
| Jun 3, 2026 | Hjartarson | ½–½ | Mantovani | Round 2: Hjartarson, Johann - Mantovani, Renzo | English Opening: Symmetrical Variation, Ultra-Symmetrical Variation | |
| Jun 2, 2026 | Verdier | 0–1 | Hjartarson | Round 1: Verdier, Patrice - Hjartarson, Johann | Modern Defense: Standard Defense | |
| Jun 1, 2026 | Degraeve | 1–0 | Hjartarson | Round 7: Degraeve, Jean-Marc - Hjartarson, Johann | Sicilian Defense: Moscow Variation, Main Line | |
| Apr 27, 2026 | David | ½–½ | Hjartarson | Round 8: David, Alberto - Hjartarson, Johann | Ruy Lopez: Closed, Flohr System | |
| Apr 26, 2026 | Hjartarson | 1–0 | Agdestein | Round 7: Hjartarson, Johann - Agdestein, Simen | Caro-Kann Defense: Advance Variation, Botvinnik-Carls Defense | |
| Apr 25, 2026 | Bryson | ½–½ | Hjartarson | Round 6: Bryson, Douglas M - Hjartarson, Johann | Scotch Game: Göring Gambit, Double Pawn Sacrifice | |
| Apr 23, 2026 | Hjartarson | 0–1 | Czebe | Round 5: Hjartarson, Johann - Czebe, Attila | Philidor Defense: Lion Variation | |
| Apr 22, 2026 | Ledger | ½–½ | Hjartarson | Round 4: Ledger, Andrew J - Hjartarson, Johann | Queen's Indian Defense: Fianchetto Variation, Nimzowitsch Variation | |
| Apr 21, 2026 | Hjartarson | ½–½ | Adams | Round 3: Hjartarson, Johann - Adams, Michael | Ruy Lopez: Morphy Defense, Neo-Arkhangelsk Variation | |
| Apr 20, 2026 | Forchert | 0–1 | Hjartarson | Round 2: Forchert, Martin - Hjartarson, Johann | Sicilian Defense: Najdorf Variation, English Attack | |
| Apr 18, 2026 | Ehlvest | ½–½ | Hjartarson | Round 9: Ehlvest, Jaan - Hjartarson, Johann | Ruy Lopez: Closed, Flohr System | |
| Mar 8, 2026 | Hjartarson | 0–1 | Briem | Icelandic team chess championship premier league | Italian Game: Classical Variation, Giuoco Pianissimo | |
| Mar 7, 2026 | Domalchuk-Jonasson | ½–½ | Hjartarson | Icelandic team chess championship premier league | Nimzo-Indian Defense: Classical Variation | |
| Mar 6, 2026 | Stremavicius | ½–½ | Hjartarson | Icelandic team chess championship premier league | King's Indian Defense: Normal Variation, Rare Defenses | |
| Mar 5, 2026 | Petrov | 1–0 | Hjartarson | Icelandic team chess championship premier league | Nimzo-Indian Defense: Classical Variation, Berlin Variation | |
| Feb 8, 2026 | Mitusov | * | Hjartarson | Eliteserien 2025-26 | Sicilian Defense: Kan Variation, Maróczy Bind, Réti Variation | |
| Feb 7, 2026 | Hjartarson | 0–1 | Stokke | Eliteserien 2025-26 | King's Indian Defense: Petrosian Variation, Stein Defense | |
| Feb 6, 2026 | Oksendal | 0–1 | Hjartarson | Eliteserien 2025-26 | Pirc Defense: Austrian Attack, Weiss Variation | |
| Dec 7, 2025 | Hjartarson | 1–0 | Gretarsson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Modern Defense | |
| Dec 7, 2025 | Heimisson | 0–1 | Hjartarson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | King's Indian Attack: Spassky Variation | |
| Dec 7, 2025 | Hjartarson | 1–0 | Stefansson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Sicilian Defense: Boleslavsky Variation | |
| Dec 7, 2025 | Thorhallsson | ½–½ | Hjartarson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Italian Game: Classical Variation, Giuoco Pianissimo | |
| Dec 7, 2025 | Thorfinnsson | 1–0 | Hjartarson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | King's Indian Defense: Four Pawns Attack | |
| Dec 7, 2025 | Hjartarson | 1–0 | Olafsson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Sicilian Defense: Kan Variation, Modern Variation | |
| Dec 7, 2025 | Ragnarsson | 0–1 | Hjartarson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Alekhine Defense: Four Pawns Attack, Main Line | |
| Dec 6, 2025 | Hjartarson | 1–0 | Thorfinnsson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Italian Game: Classical Variation, Giuoco Pianissimo, Albin Variation | |
| Dec 6, 2025 | Hjartarson | 1–0 | Stefansson | Friðriksmót Landsbankans – Íslandsmótið í hraðskák | Sicilian Defense: Open | |
| Nov 16, 2025 | Ostrovskiy | 0–1 | Hjartarson | Icelandic team chess championship premier league | Alekhine Defense: Exchange Variation | |
| Nov 15, 2025 | Hjartarson | 1–0 | Gretarsson | Icelandic team chess championship premier league | Italian Game: Two Knights Defense, Modern Bishop's Opening | |
| Nov 15, 2025 | O`Donnell | 0–1 | Hjartarson | Icelandic team chess championship premier league | Nimzo-Indian Defense: Classical Variation, Berlin Variation | |
| Nov 14, 2025 | Hjartarson | ½–½ | Bogdanov | Icelandic team chess championship premier league | Queen's Gambit Declined: Vienna Variation, Quiet Variation | |
| Oct 19, 2025 | Hjartarson | 0–1 | Gelfand | Round 1: Hjartarson, Johann - Gelfand, Boris | Nimzo-Indian Defense: Normal Variation, Botvinnik System | |
| Apr 15, 2025 | Hjartarson | 0–1 | Ivic | Reykjavik Open 2025 | Queen's Gambit Declined: Hastings Variation | |
| Apr 14, 2025 | Haug | 0–1 | Hjartarson | Reykjavik Open 2025 | Modern Defense | |
| Apr 13, 2025 | Hjartarson | 1–0 | Terrieux | Reykjavik Open 2025 | English Opening: King's English Variation, Taimanov Variation | |
| Apr 13, 2025 | Safarli | 1–0 | Hjartarson | Reykjavik Open 2025 | Italian Game: Classical Variation, Greco Gambit, Traditional Line | |
| Apr 12, 2025 | Migot | 0–1 | Hjartarson | Reykjavik Open 2025 | Ruy Lopez: Morphy Defense, Neo-Arkhangelsk Variation | |
| Apr 11, 2025 | Hjartarson | ½–½ | Borne | Reykjavik Open 2025 | Nimzo-Indian Defense: Normal Variation, Botvinnik System | |
| Apr 10, 2025 | Hjartarson | 1–0 | Unzicker | Reykjavik Open 2025 | Sicilian Defense: Richter-Rauzer Variation, Neo-Modern Variation | |
| Apr 9, 2025 | Ponnio | 0–1 | Hjartarson | Reykjavik Open 2025 | King's Indian Defense: Sämisch Variation, Closed Variation, Main Line | |
| Feb 26, 2025 | Hjartarson | ½–½ | Ftacnik | WSTCC | Sicilian Defense: Scheveningen Variation, Classical Variation | |
| Feb 25, 2025 | David | ½–½ | Hjartarson | WSTCC | Modern Defense: Standard Defense | |
| Feb 24, 2025 | Van der Werf | 0–1 | Hjartarson | WSTCC | Nimzo-Indian Defense: Normal Variation, Botvinnik System | |
| Feb 23, 2025 | Hjartarson | 0–1 | Adams | WSTCC | Ruy Lopez: Marshall Attack | |
| Feb 20, 2025 | Hjartarson | 0–1 | Kazhgaleyev | WSTCC | Sicilian Defense: Accelerated Dragon, Maróczy Bind | |
| Feb 19, 2025 | Wang | 0–1 | Hjartarson | WSTCC | Modern Defense: Standard Defense | |
| Feb 18, 2025 | Hjartarson | ½–½ | Davies | WSTCC | Sicilian Defense: Kan Variation, Polugaevsky Variation | |
| Feb 17, 2025 | Lauterbach | 0–1 | Hjartarson | WSTCC | Sicilian Defense: French Variation | |
| Oct 25, 2024 | Hjartarson | ½–½ | Elmi | 39th European Chess Club Cup | Sicilian Defense: Kan Variation, Polugaevsky Variation | |
| Oct 24, 2024 | Nemeth | 0–1 | Hjartarson | 39th European Chess Club Cup | ? | |
| Oct 23, 2024 | Hjartarson | 0–1 | Cumming | 39th European Chess Club Cup | English Opening: King's English Variation, Adhiban Gambit | |
| Oct 22, 2024 | Smirin | 0–1 | Hjartarson | 39th European Chess Club Cup | Ruy Lopez: Closed, Chigorin Defense | |
| Oct 21, 2024 | Hjartarson | ½–½ | Eilenberg | 39th European Chess Club Cup | Slav Defense: Czech Variation, Bled Attack | |
| Jul 11, 2024 | Paschall | 0–1 | Hjartarson | 50-1 | English Opening: Anglo-Indian Defense, Queen's Indian Formation | |
| Jul 10, 2024 | Mrva | 1–0 | Hjartarson | 50-1 | Ruy Lopez: Closed, Smyslov Defense | |
| Jul 9, 2024 | Hjartarson | ½–½ | Ehlvest | 50-1 | Queen's Gambit Declined: Orthodox Defense, Main Line | |
| Jul 7, 2024 | Hjartarson | 1–0 | Cummings | 50-1 | Caro-Kann Defense: Advance Variation, Short Variation | |
| Jul 6, 2024 | Godena | ½–½ | Hjartarson | 50-1 | Scotch Game: Schmidt Variation | |
| Jul 5, 2024 | Adams | 1–0 | Hjartarson | 50-1 | Sicilian Defense: French Variation | |
| Jul 4, 2024 | Hjartarson | 1–0 | Lampe | 50-1 | King's Indian Defense: Orthodox Variation, Positional Defense | |
| Jul 4, 2024 | Kaspi | 0–1 | Hjartarson | 50-1 | Nimzo-Indian Defense: Rubinstein System | |
| May 15, 2024 | Ostergaard | 0–1 | Hjartarson | European Senior Team Chess Championship 2024 - Section 50 + | Queen's Indian Defense: Kasparov-Petrosian Variation, Kasparov Attack | |
| May 14, 2024 | Hjartarson | 1–0 | Sielecki | European Senior Team Chess Championship 2024 - Section 50 + | Sicilian Defense: Dragon Variation, Classical Variation | |
| May 13, 2024 | Emms | ½–½ | Hjartarson | European Senior Team Chess Championship 2024 - Section 50 + | Modern Defense | |
| May 12, 2024 | Hjartarson | 1–0 | Mrva | European Senior Team Chess Championship 2024 - Section 50 + | King's Indian Defense: Orthodox Variation, Bayonet Attack | |
| May 11, 2024 | David | ½–½ | Hjartarson | European Senior Team Chess Championship 2024 - Section 50 + | Nimzo-Indian Defense: Normal Variation, Classical Defense | |
| May 10, 2024 | Hjartarson | 1–0 | Csiszar | European Senior Team Chess Championship 2024 - Section 50 + | Blumenfeld Countergambit Accepted | |
| May 8, 2024 | Hjartarson | 1–0 | Dishman | European Senior Team Chess Championship 2024 - Section 50 + | Caro-Kann Defense: Advance Variation, Botvinnik-Carls Defense | |
| May 7, 2024 | Frostick | 0–1 | Hjartarson | European Senior Team Chess Championship 2024 - Section 50 + | Sicilian Defense: Delayed Alapin Variation | |
| Mar 21, 2024 | Unzicker | 0–1 | Hjartarson | Reykjavik Open 2024 | English Opening: King's English Variation, Four Knights Variation, Fianchetto Line, with Nb6 | |
| Mar 20, 2024 | Hjartarson | 0–1 | Pultinevicius | Reykjavik Open 2024 | Caro-Kann Defense: Advance Variation, Tal Variation | |
| Mar 19, 2024 | Mardell | 0–1 | Hjartarson | Reykjavik Open 2024 | Nimzo-Indian Defense: Reshevsky Variation | |
| Mar 18, 2024 | Hjartarson | ½–½ | Sushanth Kamabathula | Reykjavik Open 2024 | King's Indian Defense: Petrosian Variation, Normal Defense | |
| Mar 18, 2024 | Bisby | 0–1 | Hjartarson | Reykjavik Open 2024 | Italian Game: Classical Variation, Center Attack | |
| Mar 17, 2024 | Hjartarson | 1–0 | Li | Reykjavik Open 2024 | Ruy Lopez: Morphy Defense | |
| Mar 15, 2024 | Hjartarson | ½–½ | Ptacnikova | Reykjavik Open 2024 | Queen's Indian Defense: Spassky System | |
| Oct 20, 2024 | Sarana | 1–0 | Hjartarson | Round 1: Sarana, Alexey - Hjartarson, Johann | Nimzo-Indian Defense: Classical Variation | |
| Dec 16, 2023 | Hjartarson | 0–1 | Safarli | European Blitz Championship | Sicilian Defense: Old Sicilian | |
| Dec 16, 2023 | Hjartarson | 1–0 | Vyval | European Blitz Championship | English Opening: Agincourt Defense | |
| Dec 16, 2023 | Hjartarson | 0–1 | Balog | European Blitz Championship | French Defense: Advance Variation, Wade Variation | |