| Oct 16, 2025 | Schreidl | 1–0 | Heitmann | Runde 7: Schreidl, Michael - Heitmann, Erik | King's Indian Attack | |
| Jul 24, 2025 | Heitmann | 0–1 | Christoffersen | Biel Chess Festival 2025 | Semi-Slav Defense: Noteboom Variation | |
| Jul 23, 2025 | Kulikov | 1–0 | Heitmann | Biel Chess Festival 2025 | Sicilian Defense: Najdorf Variation, Adams Attack | |
| Jul 22, 2025 | Heitmann | 1–0 | Srirasa | Biel Chess Festival 2025 | Queen's Gambit Declined | |
| Jul 21, 2025 | Steiner | ½–½ | Heitmann | Biel Chess Festival 2025 | ? | |
| Jul 20, 2025 | Avilova | 1–0 | Heitmann | Biel Chess Festival 2025 Blitz | Réti Opening: Advance Variation | |
| Jul 20, 2025 | Heitmann | * | Freuler | Biel Chess Festival 2025 Blitz | Benko Gambit Accepted: Modern Variation | |
| Jul 20, 2025 | Heitmann | 0–1 | Fabre | Biel Chess Festival 2025 Blitz | King's Indian Defense: Sämisch Variation, Panno Formation | |
| Jul 20, 2025 | Gautschi | 0–1 | Heitmann | Biel Chess Festival 2025 Blitz | Queen's Pawn Game: Colle System | |
| Jul 20, 2025 | Heitmann | 1–0 | Egli | Biel Chess Festival 2025 Blitz | Pterodactyl Defense: Queen Pterodactyl, Quiet Line | |
| Jul 20, 2025 | Hess | 1–0 | Heitmann | Biel Chess Festival 2025 Blitz | Sicilian Defense: Wing Gambit | |
| Jul 20, 2025 | Bai | 0–1 | Heitmann | Biel Chess Festival 2025 Blitz | Sicilian Defense: Najdorf Variation, Adams Attack | |
| Jul 20, 2025 | Heitmann | 1–0 | Doxarve | Biel Chess Festival 2025 Blitz | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Jul 19, 2025 | Heitmann | 1–0 | Steiner | Biel Chess Festival 2025 | King's Indian Defense: Sämisch Variation | |
| Jul 18, 2025 | Hasini Kamabathula | 1–0 | Heitmann | Biel Chess Festival 2025 | Sicilian Defense: Najdorf Variation, Adams Attack | |
| Jul 17, 2025 | Heitmann | 1–0 | Panda | Biel Chess Festival 2025 | Queen's Gambit Declined: Charousek Variation | |
| Jul 16, 2025 | Filimonov | 1–0 | Heitmann | Biel Chess Festival 2025 | Sicilian Defense: Najdorf Variation, Zagreb Variation | |
| Jul 15, 2025 | Heitmann | 1–0 | Wipf | Biel Chess Festival 2025 | Slav Defense: Modern Line | |
| Jun 14, 2025 | Sniegowski | ½–½ | Heitmann | ODJM B 2025 | King's Indian Attack | |
| Jun 13, 2025 | Heitmann | 1–0 | Geschke | ODJM B 2025 | King's Indian Defense: Sämisch Variation, Closed Variation | |
| Jun 12, 2025 | Schmidt | 0–1 | Heitmann | ODJM B 2025 | Indian Defense: Spielmann-Indian | |
| Jun 11, 2025 | Heitmann | 1–0 | Schiewe | ODJM B 2025 | Queen's Gambit Declined | |
| Jun 11, 2025 | Kautny | 1–0 | Heitmann | ODJM B 2025 | Sicilian Defense: Wing Gambit | |
| Jun 10, 2025 | Ebel | 0–1 | Heitmann | ODJM B 2025 | Sicilian Defense: Modern Variations | |
| Jun 9, 2025 | Heitmann | 0–1 | Golke | ODJM B 2025 | Nimzo-Indian Defense: Rubinstein System | |
| Jun 8, 2025 | Reuss | ½–½ | Heitmann | ODJM B 2025 | Sicilian Defense: Closed | |
| Jun 8, 2025 | Heitmann | 1–0 | Meller | ODJM B 2025 | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| May 25, 2024 | Heitmann | 1–0 | Schellinger | DEM U12 2024 | Nimzo-Indian Defense: Classical Variation, Noa Variation | |
| May 24, 2024 | Heins | 1–0 | Heitmann | DEM U12 2024 | Scandinavian Defense: Main Line | |
| May 23, 2024 | Heitmann | ½–½ | Hepp | DEM U12 2024 | Zukertort Opening: Quiet System | |
| May 22, 2024 | Heitmann | 0–1 | Vinogradov | DEM U12 2024 | Zukertort Opening: Quiet System | |
| May 22, 2024 | Franke | 0–1 | Heitmann | DEM U12 2024 | Scandinavian Defense: Main Line | |
| May 21, 2024 | Wagener | ½–½ | Heitmann | DEM U12 2024 | Scandinavian Defense: Main Line | |
| May 20, 2024 | Heitmann | 0–1 | Fels | DEM U12 2024 | Semi-Slav Defense: Accelerated Move Order | |
| May 19, 2024 | Heitmann | 1–0 | Hoppe | DEM U12 2024 | Grünfeld Defense: Exchange Variation | |
| May 19, 2024 | Shevchenko | 1–0 | Heitmann | DEM U12 2024 | English Opening: Symmetrical Variation, Anti-Benoni Variation | |
| Jun 11, 2022 | Mulgunov | 1–0 | Heitmann | DEM U10 2022 | Sicilian Defense: Pin Variation | |
| Jun 10, 2022 | Heitmann | 0–1 | Hagn | DEM U10 2022 | Slav Defense: Geller Gambit | |
| Jun 10, 2022 | Rohatgi | 1–0 | Heitmann | DEM U10 2022 | Sicilian Defense: Najdorf Variation, English Attack | |
| Jun 9, 2022 | Heitmann | 1–0 | Wang | DEM U10 2022 | Italian Game: Classical Variation, Greco Gambit | |
| Jun 8, 2022 | Heitmann | 0–1 | Junge | DEM U10 2022 | King's Indian Defense: Petrosian Variation, Normal Defense | |
| Jun 8, 2022 | Fadeev | 1–0 | Heitmann | DEM U10 2022 | Sicilian Defense: Najdorf Variation, English Attack | |
| Jun 7, 2022 | Chua | 0–1 | Heitmann | DEM U10 2022 | Sicilian Defense: Smith-Morra Gambit Deferred | |
| Jun 6, 2022 | Heitmann | 0–1 | Allen | DEM U10 2022 | Semi-Slav Defense: Accelerated Move Order | |
| Jun 6, 2022 | Fels | 0–1 | Heitmann | DEM U10 2022 | Rapport-Jobava System | |
| Jun 5, 2022 | Heitmann | 0–1 | Rau | DEM U10 2022 | Nimzo-Indian Defense: Leningrad Variation | |
| Jun 5, 2022 | Li | * | Heitmann | DEM U10 2022 | Sicilian Defense: Najdorf Variation, English Attack | |
| Aug 29, 2021 | Ley | 1–0 | Heitmann | DEM U10 2021 | Sicilian Defense: Closed | |
| Aug 28, 2021 | Heitmann | 1–0 | Deiringer | DEM U10 2021 | Indian Defense | |
| Aug 28, 2021 | Junge | 1–0 | Heitmann | DEM U10 2021 | Elephant Gambit | |
| Aug 27, 2021 | Heitmann | 1–0 | Grebita | DEM U10 2021 | Scotch Game: Scotch Gambit, Advance Variation | |
| Aug 26, 2021 | Heitmann | 1–0 | Schröder | DEM U10 2021 | Queen's Pawn Game: Accelerated London System | |
| Aug 26, 2021 | Gavrylyuk | ½–½ | Heitmann | DEM U10 2021 | Queen's Pawn Game: Accelerated London System | |
| Aug 25, 2021 | Akcapinar | 1–0 | Heitmann | DEM U10 2021 | Sicilian Defense: Najdorf Variation, Opocensky Variation, Traditional Line | |
| Aug 24, 2021 | Heitmann | 0–1 | Prashanthakumar | DEM U10 2021 | Indian Defense | |
| Aug 24, 2021 | Rohatgi | 1–0 | Heitmann | DEM U10 2021 | Sicilian Defense: Najdorf Variation, Opocensky Variation | |
| Aug 23, 2021 | Heitmann | 1–0 | Lange | DEM U10 2021 | Queen's Pawn Game: Accelerated London System | |
| Aug 23, 2021 | Herrmann | 1–0 | Heitmann | DEM U10 2021 | Sicilian Defense: Najdorf Variation, Opocensky Variation | |
| — | Kemna | 1–0 | Heitmann | Round 1: Kemna, Martin - Heitmann, Erik | Semi-Slav Defense: Main Line | |