| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 1. T Southam vs P Claesen |
| 1-0 | 35 | 1984 | World Championship (U16) | D18 Queen's Gambit Declined Slav, Dutch |
| 2. P Claesen vs D Sadkowski |
| 0-1 | 14 | 1988 | Belgian Championship | A14 English |
| 3. P Claesen vs G Canfell |
| ½-½ | 59 | 1988 | World Junior Championship | E77 King's Indian |
| 4. I D MacKay vs P Claesen |
| 1-0 | 57 | 1988 | World Junior Championship | D10 Queen's Gambit Declined Slav |
| 5. P Claesen vs J Kuffer |
| 1-0 | 17 | 1988 | World Junior Championship | A29 English, Four Knights, Kingside Fianchetto |
| 6. P R Cooper vs P Claesen |
| ½-½ | 20 | 1988 | World Junior Championship | C17 French, Winawer, Advance |
| 7. M Schlosser vs P Claesen |
| 1-0 | 40 | 1988 | World Junior Championship | C02 French, Advance |
| 8. P Claesen vs Z Rahman |
| ½-½ | 43 | 1988 | World Junior Championship | A13 English |
| 9. P Claesen vs E Hernandez Guerrero |
| 1-0 | 41 | 1988 | World Junior Championship | D34 Queen's Gambit Declined, Tarrasch |
| 10. T Southam vs P Claesen |
| 1-0 | 25 | 1988 | World Junior Championship | D15 Queen's Gambit Declined Slav |
| 11. P Claesen vs E T Ng |
| 1-0 | 38 | 1988 | World Junior Championship | B07 Pirc |
| 12. M Ballmann vs P Claesen |
| ½-½ | 15 | 1988 | World Junior Championship | C17 French, Winawer, Advance |
| 13. D Adla vs P Claesen |
 | 1-0 | 41 | 1988 | World Junior Championship | D17 Queen's Gambit Declined Slav |
| 14. P Claesen vs K McCann |
| 1-0 | 41 | 1988 | World Junior Championship | A18 English, Mikenas-Carls |
| 15. D Norwood vs P Claesen |
| 1-0 | 56 | 1988 | World Junior Championship | A00 Uncommon Opening |
| 16. P Claesen vs Topalov |
| ½-½ | 27 | 1989 | European Junior Championship 1989/90 | A27 English, Three Knights System |
| 17. T Fogarasi vs P Claesen |
| ½-½ | 23 | 1989 | European Junior Championship 1989/90 | C18 French, Winawer |
| 18. P Claesen vs I J Markovic |
| ½-½ | 32 | 1989 | European Junior Championship 1989/90 | A29 English, Four Knights, Kingside Fianchetto |
| 19. K Ruxton vs P Claesen |
| 1-0 | 30 | 1989 | European Junior Championship 1989/90 | C05 French, Tarrasch |
| 20. P Claesen vs V Miguel Lago |
| ½-½ | 47 | 1989 | European Junior Championship 1989/90 | A37 English, Symmetrical |
| 21. M Morais vs P Claesen |
| 1-0 | 49 | 1989 | European Junior Championship 1989/90 | C05 French, Tarrasch |
| 22. P Claesen vs D Petrone |
| ½-½ | 45 | 1989 | European Junior Championship 1989/90 | A29 English, Four Knights, Kingside Fianchetto |
| 23. J Stafrace vs P Claesen |
| 0-1 | 28 | 1989 | European Junior Championship 1989/90 | D10 Queen's Gambit Declined Slav |
| 24. T Demirel vs P Claesen |
| ½-½ | 22 | 1989 | European Junior Championship 1989/90 | B10 Caro-Kann |
| 25. P Claesen vs N Borge |
| 1-0 | 42 | 1989 | European Junior Championship 1989/90 | A16 English |
Kibitzing
