| Jun 7, 2026 | Steinhauer | 1–0 | Koellner | Round 7: Steinhauer, Artur - Koellner, Christof | Philidor Defense: Exchange Variation | |
| Jun 5, 2026 | Boidman | 1–0 | Koellner | Round 3: Boidman, Yuri - Koellner, Christof | Pirc Defense | |
| May 22, 2026 | Narayanan S L | 1–0 | Koellner | Runde 2: Narayanan S L - Koellner, Christof | Philidor Defense: Lion Variation | |
| Apr 2, 2026 | Willems | 1–0 | Koellner | Grenke Chess Festival 2026 Open | English Opening: Agincourt Defense | |
| Jun 1, 2024 | Koellner | 0–1 | Hinrichs | Round 5: Koellner, Christof - Hinrichs, Paul | Queen's Pawn Game: Colle System | |
| May 31, 2024 | Koellner | ½–½ | Chassard | Round 3: Koellner, Christof - Chassard, Cedric | Indian Defense: Spielmann-Indian | |
| May 30, 2024 | Endres | * | Koellner | Round 2: Endres, Thomas - Koellner, Christof | ? | |
| Apr 14, 2024 | Buechele | 0–1 | Koellner | Oberliga W?rttemberg Schlussrunde 2024 | Indian Defense: Wade-Tartakower Defense | |
| Mar 24, 2024 | Koellner | 0–1 | Eric | SK Schwäbisch Hall - SF Deizisau 2 | Indian Defense: Knights Variation | |
| Jan 7, 2024 | Fiorito | * | Koellner | Roquetas 2024 | ? | |
| Jan 6, 2024 | Koellner | * | Schenderowitsch | Roquetas 2024 | ? | |
| Jan 6, 2024 | Sukhodolskyi | * | Koellner | Roquetas 2024 | ? | |
| Jan 5, 2024 | Koellner | * | Marin Badenas | Roquetas 2024 | ? | |
| Jan 4, 2024 | Koellner | * | Castillo Ojeda | Roquetas 2024 | ? | |
| Jan 4, 2024 | Carmona Huertas | * | Koellner | Roquetas 2024 | ? | |
| Jan 3, 2024 | Koellner | * | Bangiev | Roquetas 2024 | ? | |
| Jan 3, 2024 | Domene Mulyukov | * | Koellner | Roquetas 2024 | ? | |
| Jan 2, 2024 | Merario Alarcon | 1–0 | Koellner | Roquetas 2024 | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Nov 5, 2023 | Lahouel | 0–1 | Koellner | Heilbronner SV 2 - SF Deizisau 2 | Pirc Defense | |
| Oct 15, 2023 | Maeurer | ½–½ | Koellner | SF Deizisau 2 - Stuttgarter SF | King's Indian Attack: Keres Variation | |
| Nov 13, 2022 | Joel Paul Ganta | * | Koellner | 25th Open Bavarian Championship | ? | |
| Nov 12, 2022 | Koellner | * | Juergens | 25th Open Bavarian Championship | ? | |
| Nov 11, 2022 | Schmidt | 0–1 | Koellner | 25th Open Bavarian Championship | ? | |
| Nov 10, 2022 | Koellner | 0–1 | Jahncke | 25th Open Bavarian Championship | ? | |
| Nov 9, 2022 | Leeb | ½–½ | Koellner | 25th Open Bavarian Championship | Philidor Defense: Lion Variation | |
| Nov 8, 2022 | Koellner | 1–0 | Hentze | 25th Open Bavarian Championship | ? | |
| Nov 7, 2022 | Epding | ½–½ | Koellner | 25th Open Bavarian Championship | ? | |
| Nov 6, 2022 | Koellner | ½–½ | Rheinwalt | 25th Open Bavarian Championship | ? | |
| Feb 6, 2022 | Hommer | 0–1 | Koellner | chessemy open 2022 | ? | |
| Feb 5, 2022 | Pellicoro | 0–1 | Koellner | chessemy open 2022 | Sicilian Defense: Delayed Alapin Variation, with e6 | |
| Feb 4, 2022 | Koellner | 0–1 | Koellner | chessemy open 2022 | Pseudo Queen's Indian Defense | |
| Feb 3, 2022 | Borkhardt | 0–1 | Koellner | chessemy open 2022 | Philidor Defense: Lion Variation | |
| Feb 2, 2022 | Koellner | 0–1 | Schulze | chessemy open 2022 | Torre Attack: Classical Defense, Nimzowitsch Variation | |
| Feb 1, 2022 | Weyandt | 0–1 | Koellner | chessemy open 2022 | Rat Defense: Fuller Gambit | |
| Jan 31, 2022 | Koellner | 0–1 | Skytte | chessemy open 2022 | Trompowsky Attack | |
| Jan 30, 2022 | Tan | 0–1 | Koellner | chessemy open 2022 | Lion Defense: Lion's Jaw | |
| Jan 29, 2022 | Koellner | 1–0 | Zoellner | chessemy open 2022 | Trompowsky Attack | |
| Sep 14, 2021 | Koellner | ½–½ | Laux | 1st Int. Swiss Masters Baden-Baden | Horwitz Defense | |
| Sep 13, 2021 | von Mettenheim | 1–0 | Koellner | 1st Int. Swiss Masters Baden-Baden | Philidor Defense: Lion Variation, Shirov Gambit | |
| Sep 13, 2021 | Mattenberger | 0–1 | Koellner | 1st Int. Swiss Masters Baden-Baden | Rat Defense: English Rat | |
| Sep 12, 2021 | Koellner | 0–1 | Papadiamandis | 1st Int. Swiss Masters Baden-Baden | East Indian Defense | |
| Sep 11, 2021 | Koellner | ½–½ | Hagner | 1st Int. Swiss Masters Baden-Baden | Slav Defense: Exchange Variation, Boor Attack | |
| Sep 11, 2021 | Parvanyan | 1–0 | Koellner | 1st Int. Swiss Masters Baden-Baden | Bogo-Indian Defense: Retreat Variation | |
| Sep 10, 2021 | Koellner | 1–0 | Hommer | 1st Int. Swiss Masters Baden-Baden | Queen's Pawn Game: Colle System, Traditional Colle | |
| Sep 10, 2021 | Gut | 0–1 | Koellner | 1st Int. Swiss Masters Baden-Baden | Rat Defense: English Rat | |
| Sep 9, 2021 | Koellner | 0–1 | Koellner | 1st Int. Swiss Masters Baden-Baden | Italian Game: Classical Variation, Greco Gambit | |
