| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 1. A Schmied vs J Thomassen |
| 1-0 | 35 | 2004 | Politiken Cup | D66 Queen's Gambit Declined, Orthodox Defense, Bd3 line |
| 2. A Pedersen vs J Thomassen |
| 1-0 | 28 | 2004 | Politiken Cup | D63 Queen's Gambit Declined, Orthodox Defense |
| 3. J Thomassen vs P Cech |
| 0-1 | 25 | 2005 | Politiken Cup | D18 Queen's Gambit Declined Slav, Dutch |
| 4. H Ochtman vs J Thomassen |
| 1-0 | 31 | 2005 | Politiken Cup | A02 Bird's Opening |
| 5. J Gilbert vs J Thomassen |
| 0-1 | 31 | 2005 | Gausdal Byggern Masters | E32 Nimzo-Indian, Classical |
| 6. J Thomassen vs J Hector |
| 1-0 | 46 | 2006 | Politiken Cup | C78 Ruy Lopez |
| 7. A Wiwe vs J Thomassen |
| 0-1 | 36 | 2006 | Politiken Cup | B99 Sicilian, Najdorf, 7...Be7 Main line |
| 8. J Thomassen vs C Rasmussen |
| 0-1 | 16 | 2006 | Politiken Cup | C42 Petrov Defense |
| 9. J Schultz-Pedersen vs J Thomassen |
| 1-0 | 37 | 2006 | Politiken Cup | B23 Sicilian, Closed |
| 10. J Thomassen vs J H Hansen |
| 1-0 | 65 | 2006 | Politiken Cup | B32 Sicilian |
| 11. D Dragicevic vs J Thomassen |
 | 1-0 | 51 | 2006 | Politiken Cup | B99 Sicilian, Najdorf, 7...Be7 Main line |
| 12. J Thomassen vs M Tudvad |
| 1-0 | 23 | 2006 | Politiken Cup | C18 French, Winawer |
| 13. P Dalberg vs J Thomassen |
| ½-½ | 47 | 2006 | Politiken Cup | A25 English |
| 14. G Kafka vs J Thomassen |
| 1-0 | 34 | 2006 | Politiken Cup | B25 Sicilian, Closed |
| 15. L Milman vs J Thomassen |
| 0-1 | 78 | 2007 | Pula Open | C85 Ruy Lopez, Exchange Variation Doubly Deferred (DERLD) |
| 16. J Thomassen vs M Lanzani |
| ½-½ | 27 | 2007 | Pula Open | D34 Queen's Gambit Declined, Tarrasch |
| 17. J Thomassen vs E Blomqvist |
| ½-½ | 48 | 2007 | Politiken Cup | D10 Queen's Gambit Declined Slav |
| 18. S Christensen vs J Thomassen |
| ½-½ | 36 | 2007 | Politiken Cup | B22 Sicilian, Alapin |
| 19. J Thomassen vs S Holm |
| ½-½ | 35 | 2007 | Politiken Cup | D33 Queen's Gambit Declined, Tarrasch |
| 20. P N Andreasen vs J Thomassen |
| 0-1 | 64 | 2007 | Politiken Cup | A00 Uncommon Opening |
| 21. R Skytte vs J Thomassen |
| ½-½ | 15 | 2007 | Politiken Cup | B25 Sicilian, Closed |
| 22. J Thomassen vs C Bleis |
| 1-0 | 25 | 2007 | Politiken Cup | A81 Dutch |
| 23. J Thomassen vs S Lund |
| ½-½ | 24 | 2007 | Politiken Cup | E10 Queen's Pawn Game |
| 24. B Thorfinnsson vs J Thomassen |
| 0-1 | 70 | 2007 | Politiken Cup | E06 Catalan, Closed, 5.Nf3 |
| 25. J Thomassen vs A S Rasmussen |
| 0-1 | 35 | 2007 | Politiken Cup | B17 Caro-Kann, Steinitz Variation |
Kibitzing
