| — | Stelmaszyk | 1–0 | Pipiras | new tournament description | ? | |
| Jun 7, 2026 | Stelmaszyk | ½–½ | Bargsten | Round 5: Stelmaszyk, Nico - Bargsten, Justus | Sicilian Defense: Alapin Variation | |
| Jun 7, 2026 | Stelmaszyk | 1–0 | Scheffner | Round 4: Stelmaszyk, Nico - Scheffner, Jarno | Sicilian Defense: Alapin Variation | |
| Jun 6, 2026 | Mueer | ½–½ | Stelmaszyk | Round 3: Mueer, Sebastian - Stelmaszyk, Nico | Queen's Gambit Declined: Exchange Variation, Positional Variation | |
| Jun 6, 2026 | Stelmaszyk | 1–0 | Lichtmannecker | Round 2: Stelmaszyk, Nico - Lichtmannecker, Daniel | Petrov's Defense: Damiano Variation, Kholmov Gambit | |
| Jun 5, 2026 | Pienski | 0–1 | Stelmaszyk | Round 1: Pienski, Olaf - Stelmaszyk, Nico | Pirc Defense: Austrian Attack | |
| May 29, 2026 | Stelmaszyk | ½–½ | Ciolek | Round 9: Stelmaszyk, Nico - Ciolek, Andreas | Sicilian Defense: Delayed Alapin Variation, with e6 | |
| May 28, 2026 | Weigand | 1–0 | Stelmaszyk | Round 8: Weigand, Anton - Stelmaszyk, Nico | Italian Game: Classical Variation, Giuoco Pianissimo | |
| May 27, 2026 | Stoyanov | ½–½ | Stelmaszyk | Round 7: Stoyanov, Tsvetan - Stelmaszyk, Nico | English Opening: King's English Variation, Kramnik-Shirov Counterattack | |
| May 27, 2026 | Stelmaszyk | ½–½ | Noe | Round 6: Stelmaszyk, Nico - Noe, Christopher | Scandinavian Defense: Gubinsky-Melts Defense | |
| May 26, 2026 | Stelmaszyk | 1–0 | Shen | Round 5: Stelmaszyk, Nico - Shen, Tingrui | Sicilian Defense: Alapin Variation | |
| May 25, 2026 | Chassard | ½–½ | Stelmaszyk | Round 4: Chassard, Cedric - Stelmaszyk, Nico | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack | |
| May 25, 2026 | Stelmaszyk | 0–1 | Puranik | Round 3: Stelmaszyk, Nico - Puranik, Abhimanyu | Italian Game: Two Knights Defense, Modern Bishop's Opening | |
| May 24, 2026 | Khrapko | 0–1 | Stelmaszyk | Round 2: Khrapko, Marharyta - Stelmaszyk, Nico | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack | |
| May 23, 2026 | Stelmaszyk | 1–0 | Straub | Round 1: Stelmaszyk, Nico - Straub, Juergen Dr. | Philidor Defense: Lion Variation | |
| Apr 6, 2026 | Cervelli | ½–½ | Stelmaszyk | Grenke Chess Festival 2026 Open | Sicilian Defense: Old Sicilian | |
| Apr 5, 2026 | Stelmaszyk | 0–1 | Firman | Grenke Chess Festival 2026 Open | Ruy Lopez: Morphy Defense, Classical Defense Deferred | |
| Apr 5, 2026 | Schulte-Geers | 0–1 | Stelmaszyk | Grenke Chess Festival 2026 Open | Queen's Gambit Declined: Knight Defense, Alekhine Gambit | |
| Apr 4, 2026 | Stelmaszyk | ½–½ | Karthik Venkataraman | Grenke Chess Festival 2026 Open | Sicilian Defense: Delayed Alapin Variation, with e6 | |
| Apr 4, 2026 | Stelmaszyk | 1–0 | Bashylina | Grenke Chess Festival 2026 Open | Center Game: Normal Variation | |
| Apr 3, 2026 | Kaufeld | ½–½ | Stelmaszyk | Grenke Chess Festival 2026 Open | Pirc Defense: Austrian Attack, Kurajica Variation | |
| Mar 31, 2026 | Vollbehr | ½–½ | Stelmaszyk | Runde 9: Vollbehr, Bjarne - Stelmaszyk, Nico | Queen's Pawn Game: Symmetrical Variation, Pseudo-Catalan | |
| Mar 31, 2026 | Stelmaszyk | 1–0 | Strehse | Runde 8: Stelmaszyk, Nico - Strehse, Nelson | Sicilian Defense: Alapin Variation | |
| Mar 30, 2026 | Brockhoff | 0–1 | Stelmaszyk | Runde 6: Brockhoff, Moritz - Stelmaszyk, Nico | Sicilian Defense: Lasker-Pelikan Variation, Sveshnikov Variation, Chelyabinsk Variation | |
| Mar 29, 2026 | Stelmaszyk | 1–0 | Stadler | Runde 5: Stelmaszyk, Nico - Stadler, Andreas | Ruy Lopez: Morphy Defense, Tarrasch Variation | |
| Mar 29, 2026 | Aryan Goyal | 0–1 | Stelmaszyk | Runde 4: Aryan Goyal - Stelmaszyk, Nico | Pirc Defense | |
| Mar 28, 2026 | Stelmaszyk | 1–0 | Dupuis | Runde 3: Stelmaszyk, Nico - Dupuis, Denis K | Neo-Grünfeld Defense: Classical Variation, Original Defense | |
| Mar 28, 2026 | Gerlach | 1–0 | Stelmaszyk | Runde 2: Gerlach, Felix - Stelmaszyk, Nico | King's Indian Attack | |
| Mar 27, 2026 | Raja Harshit | 1–0 | Stelmaszyk | Runde 7: Raja Harshit - Stelmaszyk, Nico | Pirc Defense: Classical Variation | |
| Mar 27, 2026 | Stelmaszyk | 1–0 | Perske | Runde 1: Stelmaszyk, Nico - Perske, Paul | Neo-Grünfeld Defense: Classical Variation, Original Defense | |
| Jan 5, 2026 | Voege | ½–½ | Stelmaszyk | Runde 7: Voege, Tobias - Stelmaszyk, Nico | English Opening: King's English Variation | |
| Jan 4, 2026 | Reimer | ½–½ | Stelmaszyk | Runde 6: Reimer, Philip - Stelmaszyk, Nico | French Defense: Advance Variation, Lputian Variation | |
| Jan 4, 2026 | Stelmaszyk | ½–½ | Plischki | Runde 5: Stelmaszyk, Nico - Plischki, Sebastian | Sicilian Defense: Alapin Variation, Barmen Defense | |
| Jan 3, 2026 | Holtwessels | 0–1 | Stelmaszyk | Runde 4: Holtwessels, Jan - Stelmaszyk, Nico | Pirc Defense: Kholmov System | |
| Jan 3, 2026 | Stelmaszyk | ½–½ | Meiwes | Runde 3: Stelmaszyk, Nico - Meiwes, Thore | Réti Opening: Anglo-Slav Variation, with g3 | |
| Jan 2, 2026 | Nechitaylo | 1–0 | Stelmaszyk | Runde 2: Nechitaylo, Nikita - Stelmaszyk, Nico | Lion Defense: Lion's Jaw | |
| Jan 2, 2026 | Stelmaszyk | 1–0 | Mueer | Runde 1: Stelmaszyk, Nico - Mueer, Sebastian | Sicilian Defense: Delayed Alapin Variation | |
| Oct 18, 2025 | Stelmaszyk | 0–1 | Polenz | Round 9: Stelmaszyk, Nico - Polenz, Fredrik | ? | |
| Oct 18, 2025 | Reimer | 0–1 | Stelmaszyk | Round 8: Reimer, Philip - Stelmaszyk, Nico | ? | |
| Oct 18, 2025 | Stelmaszyk | 1–0 | Hagemann | Round 7: Stelmaszyk, Nico - Hagemann, Sven | ? | |
| Oct 18, 2025 | Stelmaszyk | 1–0 | Weigand | Round 4: Stelmaszyk, Nico - Weigand, Anton | ? | |
| Oct 18, 2025 | Stelmaszyk | 1–0 | Petz | Round 3: Stelmaszyk, Nico - Petz, Hagen | ? | |
| Oct 18, 2025 | Nguyen | ½–½ | Stelmaszyk | Round 2: Nguyen, Phuc Nhat - Stelmaszyk, Nico | ? | |
| Oct 18, 2025 | Stelmaszyk | 1–0 | Sviridov | Round 1: Stelmaszyk, Nico - Sviridov, Vitaliy | ? | |
| Oct 17, 2025 | Fish | ½–½ | Stelmaszyk | Runde 2: SK Lehrte - Bremen | Queen's Pawn Game | |
| Oct 17, 2025 | Stelmaszyk | 1–0 | Ay | Round 21: Stelmaszyk, Nico - Ay, Furkan | Sicilian Defense: Alapin Variation | |
| Oct 17, 2025 | Ziems | 0–1 | Stelmaszyk | Round 20: Ziems, Michael - Stelmaszyk, Nico | Rat Defense: English Rat | |
| Oct 17, 2025 | Stelmaszyk | 1–0 | Nguyen | Round 19: Stelmaszyk, Nico - Nguyen, Phuc Nhat | Ruy Lopez: Morphy Defense, Tarrasch Variation | |
| Oct 17, 2025 | Sauer | 0–1 | Stelmaszyk | Round 18: Sauer, Ben - Stelmaszyk, Nico | Hungarian Opening | |
| Oct 17, 2025 | Stelmaszyk | 1–0 | Lueders Vega | Round 17: Stelmaszyk, Nico - Lueders Vega, Iago Ernst | Ruy Lopez: Morphy Defense, Tarrasch Variation | |
| Oct 17, 2025 | Schneider | 1–0 | Stelmaszyk | Round 16: Schneider, Ilja - Stelmaszyk, Nico | Pirc Defense: Classical Variation, Quiet System | |
| Oct 17, 2025 | Stelmaszyk | 1–0 | Mimkes | Round 15: Stelmaszyk, Nico - Mimkes, Antal | Sicilian Defense: Alapin Variation | |
| Oct 17, 2025 | Dahmen | 0–1 | Stelmaszyk | Round 14: Dahmen, Christoph - Stelmaszyk, Nico | Pirc Defense: Classical Variation | |
| Oct 17, 2025 | Stelmaszyk | 1–0 | Felis | Round 13: Stelmaszyk, Nico - Felis, Timo | Caro-Kann Defense: Two Knights Attack | |
| Oct 17, 2025 | Bangert | 0–1 | Stelmaszyk | Round 12: Bangert, Jonas - Stelmaszyk, Nico | Queen's Gambit Declined: Modern Variation | |
| Oct 17, 2025 | Stelmaszyk | 1–0 | Polenz | Round 11: Stelmaszyk, Nico - Polenz, Fredrik | Philidor Defense: Lion Variation, Lion's Claw, with Bc4 and h6 | |
| Oct 17, 2025 | Nietsch | 0–1 | Stelmaszyk | Round 10: Nietsch, Felix - Stelmaszyk, Nico | Pirc Defense | |
| Oct 17, 2025 | Stelmaszyk | 1–0 | Koldunov | Round 9: Stelmaszyk, Nico - Koldunov, Elena | Sicilian Defense: Alapin Variation | |
| Oct 17, 2025 | Seyrek | 0–1 | Stelmaszyk | Round 8: Seyrek, Rohat - Stelmaszyk, Nico | King's Indian Defense: Kazakh Variation | |
| Oct 17, 2025 | Stelmaszyk | 0–1 | Wetterau | Round 7: Stelmaszyk, Nico - Wetterau, Nathanael | Petrov's Defense | |
| Oct 17, 2025 | Bruehl | 0–1 | Stelmaszyk | Round 5: Bruehl, Katharina - Stelmaszyk, Nico | Pirc Defense | |
| Oct 17, 2025 | Stelmaszyk | 1–0 | Engel | Round 2: Stelmaszyk, Nico - Engel, Bruno | ? | |
| Oct 17, 2025 | Sviridov | 1–0 | Stelmaszyk | Round 3: Sviridov, Vitaliy - Stelmaszyk, Nico | Queen's Pawn Game | |
| Oct 17, 2025 | Stelmaszyk | ½–½ | Sauer | Round 4: Stelmaszyk, Nico - Sauer, Tim | Sicilian Defense: Delayed Alapin Variation | |
| Oct 17, 2025 | Ponyrko | ½–½ | Stelmaszyk | Round 1: Ponyrko, Matviy - Stelmaszyk, Nico | Queen's Pawn Game | |
| Oct 13, 2025 | Schneider | 1–0 | Stelmaszyk | Round 6: Schneider, Ilja - Stelmaszyk, Nico | ? | |
| Oct 13, 2025 | Engel | ½–½ | Stelmaszyk | Round 5: Engel, Bruno - Stelmaszyk, Nico | ? | |
| Oct 13, 2025 | Langer | 0–1 | Stelmaszyk | Round 6: Langer, Michael S. - Stelmaszyk, Nico | Caro-Kann Defense: Exchange Variation | |
| Jun 1, 2025 | Stelmaszyk | ½–½ | Reimer | Round 7: Stelmaszyk, Nico - Reimer, Philip | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack | |
| May 31, 2025 | Weigand | ½–½ | Stelmaszyk | Round 6: Weigand, Anton - Stelmaszyk, Nico | Sicilian Defense: Old Sicilian | |
| May 31, 2025 | Stelmaszyk | 1–0 | Piz | Round 5: Stelmaszyk, Nico - Piz, Maxim, Dr. | Ruy Lopez: Morphy Defense, Tarrasch Variation | |
| May 30, 2025 | Brustkern | 0–1 | Stelmaszyk | Round 3: Brustkern, Juergen - Stelmaszyk, Nico | Pirc Defense: 150 Attack | |
| May 29, 2025 | Stelmaszyk | 1–0 | Argote | Round 2: Stelmaszyk, Nico - Argote, Carlos David | Sicilian Defense: Alapin Variation | |
| May 29, 2025 | Besbudak | 0–1 | Stelmaszyk | Round 1: Besbudak, Ozgur - Stelmaszyk, Nico | Pirc Defense: Austrian Attack, Weiss Variation | |
| May 28, 2025 | Stelmaszyk | 0–1 | Vavulin | Round 4: Stelmaszyk, Nico - Vavulin, Maxim | Alekhine Defense: Four Pawns Attack, Main Line | |
| May 25, 2025 | Stelmaszyk | ½–½ | Bargsten | Round 5: Stelmaszyk, Nico - Bargsten, Justus | Sicilian Defense: Alapin Variation | |
| May 25, 2025 | Stelmaszyk | 1–0 | Tonndorf | Round 4: Stelmaszyk, Nico - Tonndorf, Matthias | Caro-Kann Defense: Two Knights Attack, Mindeno Variation | |
| May 24, 2025 | Jaeger | 0–1 | Stelmaszyk | Round 3: Jaeger, Uwe, Dr. - Stelmaszyk, Nico | Pirc Defense: Byrne Variation | |
| May 24, 2025 | Stelmaszyk | 1–0 | Kroeze | Round 2: Stelmaszyk, Nico - Kroeze, Frank | Caro-Kann Defense: Two Knights Attack | |
| May 23, 2025 | Mimkes | 0–1 | Stelmaszyk | Round 1: Mimkes, Antal - Stelmaszyk, Nico | Pirc Defense | |
| Jan 5, 2025 | Stelmaszyk | ½–½ | Meiwes | Round 7: Stelmaszyk, Nico - Meiwes, Thore | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack | |
| Jan 4, 2025 | Stelmaszyk | 1–0 | Schiller | Round 5: Stelmaszyk, Nico - Schiller, Jan-Hendrik | Sicilian Defense: Alapin Variation, Barmen Defense | |
| Jan 4, 2025 | Lammers | 1–0 | Stelmaszyk | Round 6: Lammers, Markus - Stelmaszyk, Nico | Queen's Gambit Accepted: Furman Variation | |
| Jan 3, 2025 | Stelmaszyk | ½–½ | Giorgadze | Round 3: Stelmaszyk, Nico - Giorgadze, Giorgi | French Defense: Rubinstein Variation, Blackburne Defense | |
| Jan 3, 2025 | Knuedel | 1–0 | Stelmaszyk | Round 4: Knuedel, Torben - Stelmaszyk, Nico | Sicilian Defense: Lasker-Pelikan Variation | |
| Jan 2, 2025 | Stelmaszyk | ½–½ | Mueer | Round 1: Stelmaszyk, Nico - Mueer, Sebastian | Sicilian Defense: Delayed Alapin Variation | |
| Jan 2, 2025 | Peters | 0–1 | Stelmaszyk | Round 2: Peters, Tom - Stelmaszyk, Nico | Sicilian Defense: Four Knights Variation, Exchange Variation | |
| Dec 30, 2024 | Stelmaszyk | 1–0 | Bogomolow | Round 7: Stelmaszyk, Nico - Bogomolow, Sergej | Italian Game: Two Knights Defense, Modern Bishop's Opening | |
| Dec 29, 2024 | Dehn | 0–1 | Stelmaszyk | Round 6: Dehn, Marcus - Stelmaszyk, Nico | Queen's Pawn Game | |
| Dec 28, 2024 | Buecklers | 0–1 | Stelmaszyk | Round 4: Buecklers, Martin - Stelmaszyk, Nico | King's Indian Attack | |
| Dec 27, 2024 | Stelmaszyk | ½–½ | Stopa | Round 9: Stelmaszyk, Nico - Stopa, Jacek | French Defense: Normal Variation | |
| Dec 27, 2024 | Parvanyan | ½–½ | Stelmaszyk | Round 8: Parvanyan, Ashot - Stelmaszyk, Nico | Catalan Opening: Open Defense, Classical Line | |
| Dec 27, 2024 | Stelmaszyk | ½–½ | Weigand | Round 3: Stelmaszyk, Nico - Weigand, Anton | Queen's Gambit Declined | |
| Jun 9, 2024 | Wittje | ½–½ | Stelmaszyk | Round 5: Wittje, Berthold - Stelmaszyk, Nico | King's Indian Attack: Spassky Variation | |
| Jun 9, 2024 | Stelmaszyk | ½–½ | Knuedel | Round 4: Stelmaszyk, Nico - Knuedel, Torben | Ruy Lopez: Berlin Defense, Rio Gambit Accepted | |
| Jun 8, 2024 | Stelmaszyk | 1–0 | Hampel | Round 3: Stelmaszyk, Nico - Hampel, Felix | Sicilian Defense: Alapin Variation | |
| Jun 8, 2024 | Kroeze | ½–½ | Stelmaszyk | Round 2: Kroeze, Frank - Stelmaszyk, Nico | English Opening: King's English Variation | |
| Jun 7, 2024 | Stelmaszyk | 1–0 | Martin | Round 1: Stelmaszyk, Nico - Martin, Dennis | Sicilian Defense: Alapin Variation | |
| Apr 1, 2024 | Buckels | 1–0 | Stelmaszyk | Grenke Chess Open 2024 | Indian Defense: London System | |
| Mar 31, 2024 | Stelmaszyk | 1–0 | Brandt | new tournament description | Sicilian Defense: Moscow Variation | |