| 24 jul 2026 | Heinke, Jasper 2064 | Windmueller, Simon 2088 | 1-0 | B47 Defensa Siciliana: Taimanov Variation, Bastrikov Variation | German Chess Championship 2026 | Candidates Men | 57 | Ver |
| 23 jul 2026 | Windmueller, Simon 2088 | Keyser, Robin 2181 | ½-½ | A13 Apertura Inglesa: Agincourt Defense, Bogoljubow Defense | German Chess Championship 2026 | Candidates Men | 34 | Ver |
| 22 jul 2026 | Herrmann, Arthur 2208 | Windmueller, Simon 2088 | 1-0 | C88 Apertura Española (Ruy López): Closed, Anti-Marshall | German Chess Championship 2026 | Candidates Men | 40 | Ver |
| 22 jul 2026 | Steger, Lukas Daniel 2196 | Windmueller, Simon 2088 | ½-½ | C88 Apertura Española (Ruy López): Closed, Anti-Marshall | German Chess Championship 2026 | Candidates Men | 36 | Ver |
| 21 jul 2026 | Windmueller, Simon 2088 | Malinowsky, Levi 2342 | 0-1 | D02 Sistema Londres: Poisoned Pawn Variation | German Chess Championship 2026 | Candidates Men | 32 | Ver |
| 20 jul 2026 | Nemitz, Alfred 2343 | Windmueller, Simon 2088 | 1-0 | D85 Defensa Grünfeld: Exchange Variation | German Chess Championship 2026 | Candidates Men | 27 | Ver |
| 20 jul 2026 | Windmueller, Simon 2088 | Lukas Schulz 2349 | 1-0 | D01 Rapport-Jobava System | German Chess Championship 2026 | Candidates Men | 46 | Ver |
| 19 jul 2026 | Neuhoff, Laertes 2306 | Windmueller, Simon 2088 | ½-½ | B47 Defensa Siciliana: Taimanov Variation, Bastrikov Variation | German Chess Championship 2026 | Candidates Men | 50 | Ver |
| 6 jun 2026 | Stillger, Bernhard 2228 | Windmueller, Simon 2107 | ½-½ | A05 Ataque Indio de Rey: Symmetrical Defense | 16. Rheinland-Pfalz Open | 10 | Ver |
| 30 may 2026 | Petzold, Johannes Julius 2044 | Windmueller, Simon 2183 | 0-1 | C55 Apertura Italiana: Two Knights Defense, Modern Bishop's Opening | DEM U18 2026 | 39 | Ver |
| 29 may 2026 | Windmueller, Simon 2183 | Apel, Linus 2004 | ½-½ | D02 Apertura de Peón de Dama: London System | DEM U18 2026 | 21 | Ver |
| 28 may 2026 | Trenz, Finn 2033 | Windmueller, Simon 2183 | ½-½ | A03 Apertura Bird: Dutch Variation | DEM U18 2026 | 26 | Ver |
| 27 may 2026 | Isbilir, Levin 2074 | Windmueller, Simon 2183 | ½-½ | C54 Apertura Italiana: Classical Variation, Giuoco Pianissimo | DEM U18 2026 | 24 | Ver |
| 27 may 2026 | Windmueller, Simon 2183 | Uhlmann, Tim 2083 | ½-½ | D33 Defensa Tarrasch: Dubov Tarrasch | DEM U18 2026 | 24 | Ver |
| 26 may 2026 | Windmueller, Simon 2183 | Vollbehr, Bjarne 2222 | 0-1 | C47 Apertura de los Cuatro Caballos | DEM U18 2026 | 69 | Ver |
| 25 may 2026 | Moeller, Maurin 2330 | Windmueller, Simon 2183 | 1-0 | D86 Defensa Grünfeld: Exchange Variation, Classical Variation | DEM U18 2026 | 45 | Ver |
| 24 may 2026 | Strehse, Nelson 2292 | Windmueller, Simon 2183 | 1-0 | A06 Apertura Zukertort | DEM U18 2026 | 36 | Ver |
| 8 mar 2026 | Windmueller, Simon 2169 | Berend, Elvira 2253 | 0-1 | A13 Apertura Inglesa: Agincourt Defense | Rapide Festival Nancy 2026 | 35 | Ver |
| 8 mar 2026 | Travadon, Loic 2549 | Windmueller, Simon 2169 | 1-0 | A48 Ataque Torre: Fianchetto Defense, Euwe Variation | Rapide Festival Nancy 2026 | 99 | Ver |
| 7 mar 2026 | Adrian, Leopold 2143 | Windmueller, Simon 2186 | 1-0 | A30 Apertura Inglesa: Symmetrical Variation | Blitz Festival Nancy 2026 | 28 | Ver |