| Apr 6, 2026 | Wartiovaara | 0–1 | Lahdelma | Round 3: Wartiovaara, Oliver - Lahdelma, Henri | Four Knights Game: Spanish Variation, Nimzowitsch Variation | |
| Apr 2, 2026 | Lahdelma | ½–½ | Keinanen | Round 9: Lahdelma, Henri - Keinanen, Toivo | Queen's Gambit Declined: Harrwitz Attack, Fianchetto Defense | |
| Apr 2, 2026 | Agopov | ½–½ | Lahdelma | Round 8: Agopov, Mikael - Lahdelma, Henri | Petrov's Defense: Damiano Variation, Kholmov Gambit | |
| Apr 2, 2026 | Lahdelma | 1–0 | Aalto | Round 7: Lahdelma, Henri - Aalto, Patrik | English Opening: Symmetrical Variation, Rubinstein Variation | |
| Apr 2, 2026 | Maki-Uuro | ½–½ | Lahdelma | Round 5: Maki-Uuro, Miikka - Lahdelma, Henri | Nimzo-Indian Defense: Classical Variation | |
| Apr 2, 2026 | Lahdelma | 1–0 | Norri | Round 4: Lahdelma, Henri - Norri, Joose | English Opening: Symmetrical Variation | |
| Apr 2, 2026 | Lahdelma | 1–0 | Koykka | Round 2: Lahdelma, Henri - Koykka, Pekka | English Opening: Symmetrical Variation, Botvinnik System Reversed, with Nf3 | |
| Apr 2, 2026 | Ronka | ½–½ | Lahdelma | Round 1: Ronka, Erik - Lahdelma, Henri | Nimzo-Indian Defense: Sämisch Variation | |
| Mar 26, 2026 | Luukkonen | 0–1 | Lahdelma | Round 6: Luukkonen, Tommi - Lahdelma, Henri | Queen's Gambit Accepted: Central Variation, Modern Defense | |
| Jul 20, 2025 | Paasikangas | ½–½ | Lahdelma | Round 9: Paasikangas, Johanna - Lahdelma, Henri | Scandinavian Defense: Gubinsky-Melts Defense | |
| Jul 18, 2025 | Lahdelma | 1–0 | Asikainen | Round 8: Lahdelma, Henri - Asikainen, Eeli | Queen's Gambit Declined: Tarrasch Defense, Pseudo-Tarrasch Bishop Attack | |
| Jul 18, 2025 | Valpas | 0–1 | Lahdelma | Round 7: Valpas, Jami - Lahdelma, Henri | Scandinavian Defense: Gubinsky-Melts Defense | |
| Jul 17, 2025 | Borsos | 1–0 | Lahdelma | Round 5: Borsos, Bogdan - Lahdelma, Henri | Sicilian Defense: French Variation | |
| Jul 15, 2025 | Lonnqvist | 1–0 | Lahdelma | Round 3: Lonnqvist, Henrik - Lahdelma, Henri | Modern Defense | |
| Jul 14, 2025 | Lahdelma | ½–½ | Moisio | Round 2: Lahdelma, Henri - Moisio, Miska | English Opening | |
| Jul 14, 2025 | Nisula | * | Lahdelma | Round 1: Nisula, Timo - Lahdelma, Henri | ? | |
| Apr 26, 2025 | Lahdelma | ½–½ | Sipila | Round 9: Lahdelma, Henri - Sipila, Vilka | Semi-Slav Defense: Meran Variation, Lundin Variation | |
| Apr 25, 2025 | Koykka | 1–0 | Lahdelma | Round 8: Koykka, Pekka - Lahdelma, Henri | French Defense: Steinitz Variation, Boleslavsky Variation | |
| Apr 24, 2025 | Lahdelma | ½–½ | Ronka | Round 7: Lahdelma, Henri - Ronka, Erik | Semi-Slav Defense: Stoltz Variation | |
| Apr 23, 2025 | Pitkanen | 0–1 | Lahdelma | Round 6: Pitkanen, Artturi - Lahdelma, Henri | Modern Defense | |
| Apr 22, 2025 | Wartiovaara | 1–0 | Lahdelma | Round 5: Wartiovaara, Oliver - Lahdelma, Henri | Caro-Kann Defense: Advance Variation, Tal Variation | |
| Apr 21, 2025 | Lahdelma | 1–0 | Nyysti | Round 4: Lahdelma, Henri - Nyysti, Sampsa | Nimzo-Indian Defense: Three Knights Variation | |
| Apr 20, 2025 | Luukkonen | 1–0 | Lahdelma | Round 3: Luukkonen, Tommi - Lahdelma, Henri | Scandinavian Defense: Modern Variation, Gipslis Variation | |
| Apr 19, 2025 | Lahdelma | 0–1 | Keinanen | Round 2: Lahdelma, Henri - Keinanen, Toivo | French Defense: Steiner Variation | |
| Apr 18, 2025 | Agopov | 1–0 | Lahdelma | Round 1: Agopov, Mikael - Lahdelma, Henri | Scandinavian Defense: Gubinsky-Melts Defense | |
| Sep 21, 2024 | Lahdelma | ½–½ | Cawdery | 45th FIDE Chess Olympiad | Nimzo-Larsen Attack: Modern Variation | |
| Sep 20, 2024 | Lahdelma | 0–1 | Prohaszka | 45th FIDE Chess Olympiad | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Sep 19, 2024 | Lahdelma | 1–0 | Hapaku | 45th FIDE Chess Olympiad | Queen's Indian Defense: Classical Variation, Traditional Variation, Nimzowitsch Line | |
| Sep 18, 2024 | Lahdelma | 0–1 | Flores | 45th FIDE Chess Olympiad | Nimzo-Indian Defense: Normal Variation, Gligoric System | |
| Sep 16, 2024 | Ulhaq | ½–½ | Lahdelma | 45th FIDE Chess Olympiad | Queen's Gambit Accepted: Old Variation | |
| Sep 15, 2024 | Andrianiaina | 0–1 | Lahdelma | 45th FIDE Chess Olympiad | Queen's Gambit Declined: Janowski Variation | |
| Sep 13, 2024 | Anas Khwaira | ½–½ | Lahdelma | 45th FIDE Chess Olympiad | Nimzo-Indian Defense: Normal Variation, Bernstein Defense, Exchange Line | |
| Sep 12, 2024 | Muradli | 1–0 | Lahdelma | 45th FIDE Chess Olympiad | Queen's Gambit Declined: Three Knights, Vienna Variation | |
| Sep 11, 2024 | Lahdelma | 1–0 | Adam | 45th FIDE Chess Olympiad | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Jun 13, 2024 | Lahdelma | 0–1 | Krivenko | Round 4: Lahdelma, Henri - Krivenko, Dion | Neo-Grünfeld Defense: Classical Variation, Original Defense | |
| Jun 12, 2024 | Arnav Maheshwari | ½–½ | Lahdelma | Round 3: Arnav Maheshwari - Lahdelma, Henri | Queen's Gambit Declined: Semi-Tarrasch Defense, Exchange Variation | |
| Jun 11, 2024 | Lahdelma | 0–1 | Laurusas | Round 2: Lahdelma, Henri - Laurusas, Tomas | Slav Defense | |
| Apr 3, 2024 | Lahdelma | 1–0 | Luukkonen | Round 6: Lahdelma, Henri - Luukkonen, Tommi | Zukertort Opening: Dutch Variation | |
| Mar 29, 2024 | Agopov | 1–0 | Lahdelma | Round 2: Agopov, Mikael - Lahdelma, Henri | French Defense: Winawer Variation, Poisoned Pawn Variation | |
| Mar 28, 2024 | Kallunki | 0–1 | Lahdelma | Round 9: Kallunki, Konsta - Lahdelma, Henri | Caro-Kann Defense: Two Knights Attack | |
| Mar 28, 2024 | Lahdelma | 0–1 | Valkama | Round 8: Lahdelma, Henri - Valkama, Eero | Catalan Opening: Closed | |
| Mar 28, 2024 | Koykka | 1–0 | Lahdelma | Round 7: Koykka, Pekka - Lahdelma, Henri | English Opening: Four Knights System, Nimzowitsch Variation | |
| Mar 28, 2024 | Wartiovaara | 1–0 | Lahdelma | Round 5: Wartiovaara, Oliver - Lahdelma, Henri | Caro-Kann Defense: Two Knights Attack, Mindeno Variation, Exchange Line | |
| Mar 28, 2024 | Lahdelma | 1–0 | Sipila | Round 4: Lahdelma, Henri - Sipila, Vilka | Queen's Gambit Declined: Albin Countergambit | |
| Mar 28, 2024 | Lahdelma | 0–1 | Keinanen | Round 3: Lahdelma, Henri - Keinanen, Toivo | Queen's Gambit Declined: Queen's Knight Variation | |
| Mar 28, 2024 | Lahdelma | 1–0 | Maki-Uuro | Round 1: Lahdelma, Henri - Maki-Uuro, Miikka | Slav Defense: Quiet Variation, Schallopp Defense | |
| Dec 27, 2022 | Lahdelma | 0–1 | Smirin | 50th Rilton Cup | Sicilian Defense: Alapin Variation | |
