| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. M Olszewski vs Niccolo Roncueti |
| 1-0 | 17 |
2001 |
EYCC B12 | E10 Queen's Pawn Game |
| 2. P Lagowski vs M Olszewski |
| ½-½ | 47 |
2001 |
open | C00 French Defense |
| 3. M Olszewski vs C Macdonald |
| 1-0 | 38 |
2001 |
EYCC B12 | D31 Queen's Gambit Declined |
| 4. J Skurzak vs M Olszewski |
| 0-1 | 35 |
2001 |
open | C02 French, Advance |
| 5. G Nigalidze vs M Olszewski |
| 1-0 | 34 |
2001 |
EYCC B12 | D43 Queen's Gambit Declined Semi-Slav |
| 6. M Olszewski vs Marek Kubak |
| 1-0 | 69 |
2001 |
open | D02 Queen's Pawn Game |
| 7. T Warakomski vs M Olszewski |
| ½-½ | 54 |
2001 |
EYCC B12 | B14 Caro-Kann, Panov-Botvinnik Attack |
| 8. M Olszewski vs Z Pyda |
| 0-1 | 54 |
2001 |
open | D02 Queen's Pawn Game |
| 9. M Olszewski vs Y Kuzubov |
| 1-0 | 53 |
2001 |
EYCC B12 | E10 Queen's Pawn Game |
| 10. Andrzej Bajgrowicz vs M Olszewski |
| 0-1 | 39 |
2001 |
open | D04 Queen's Pawn Game |
| 11. M Olszewski vs J Janovsky |
| 1-0 | 43 |
2001 |
EYCC B12 | E18 Queen's Indian, Old Main line, 7.Nc3 |
| 12. M Miroslaw vs M Olszewski |
| ½-½ | 79 |
2001 |
open | C05 French, Tarrasch |
| 13. M Olszewski vs V Borovikov |
| 0-1 | 67 |
2001 |
open | D02 Queen's Pawn Game |
| 14. Hadar Itzikowitz vs M Olszewski |
| ½-½ | 34 |
2001 |
EYCC B12 | C01 French, Exchange |
| 15. M Olszewski vs S Witkowski |
| ½-½ | 40 |
2001 |
open | A49 King's Indian, Fianchetto without c4 |
| 16. D Howell vs M Olszewski |
| 1-0 | 61 |
2001 |
EYCC B12 | C02 French, Advance |
| 17. J Ciruk vs M Olszewski |
| ½-½ | 35 |
2001 |
open | C05 French, Tarrasch |
| 18. Ngoc Truongson Nguyen vs M Olszewski |
| 1-0 | 69 |
2005 |
BELFORT YWCC Boys Under 16 | A45 Queen's Pawn Game |
| 19. K Van der Weide vs M Olszewski |
 | 0-1 | 46 |
2005 |
6th European Individual Championship | C45 Scotch Game |
| 20. F Beck vs M Olszewski |
| ½-½ | 31 |
2005 |
BELFORT YWCC Boys Under 16 | C47 Four Knights |
| 21. Bologan vs M Olszewski |
| 1-0 | 42 |
2005 |
5th Amplico AIG Life | C96 Ruy Lopez, Closed |
| 22. M Olszewski vs B Thorfinnsson |
| 0-1 | 60 |
2005 |
6th European Individual Championship | B90 Sicilian, Najdorf |
| 23. G Lettieri vs M Olszewski |
| 0-1 | 38 |
2005 |
BELFORT YWCC Boys Under 16 | C45 Scotch Game |
| 24. M Olszewski vs G Dizdar |
| 0-1 | 48 |
2005 |
6th European Individual Championship | C15 French, Winawer |
| 25. M Olszewski vs I Brener |
| 1-0 | 30 |
2005 |
BELFORT YWCC Boys Under 16 | B33 Sicilian |