| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. S Alonso vs M Kazhgaleyev |
| 0-1 | 45 |
1999 |
Ubeda Open | B43 Sicilian, Kan, 5.Nc3 |
| 2. S Alonso vs S Slipak |
| 0-1 | 60 |
1999 |
XXX Mar del Plata International | B18 Caro-Kann, Classical |
| 3. S Alonso vs A Hoffman |
| 0-1 | 35 |
2000 |
Najdorf mem Great fin | C11 French |
| 4. S Alonso vs R Rubio Doblas |
 | 0-1 | 75 |
2001 |
IV Open | C84 Ruy Lopez, Closed |
| 5. M Diaz Begonte vs S Alonso |
| 0-1 | 25 |
2001 |
IV Open | A45 Queen's Pawn Game |
| 6. S Garcia Martinez vs S Alonso |
| 0-1 | 46 |
2001 |
IV Open | B62 Sicilian, Richter-Rauzer |
| 7. N Cobo Prados vs S Alonso |
| 0-1 | 51 |
2001 |
IV Open | B30 Sicilian |
| 8. J Santana Martin vs S Alonso |
| 0-1 | 47 |
2001 |
IV Open | A45 Queen's Pawn Game |
| 9. J Segura Ariza vs S Alonso |
| 0-1 | 35 |
2003 |
X Anibal Open | D82 Grunfeld, 4.Bf4 |
| 10. S Alonso vs J H Gomez-Baillo |
| 0-1 | 54 |
2004 |
79th Argentine Championship | B19 Caro-Kann, Classical |
| 11. G Albarran vs S Alonso |
| 0-1 | 66 |
2004 |
Campeonato Superior | D17 Queen's Gambit Declined Slav |
| 12. S Alonso vs Shredder |
| 0-1 | 43 |
2005 |
Mercosur Cup | A00 Uncommon Opening |
| 13. F Peralta vs S Alonso |
| 0-1 | 46 |
2005 |
San Sebastian Open | B36 Sicilian, Accelerated Fianchetto |
| 14. S Alonso vs K Spraggett |
| 0-1 | 40 |
2005 |
American Continental Championship | B43 Sicilian, Kan, 5.Nc3 |
| 15. D Mieles Palau vs S Alonso |
| 0-1 | 26 |
2005 |
Mercosur Cup | B77 Sicilian, Dragon, Yugoslav Attack |
| 16. L Perdomo vs S Alonso |
| 0-1 | 35 |
2005 |
Argentinean Championship | D15 Queen's Gambit Declined Slav |
| 17. P Toloza vs S Alonso |
| 0-1 | 33 |
2005 |
American Continental Championship | D15 Queen's Gambit Declined Slav |
| 18. S Alonso vs D Valerga |
| 0-1 | 35 |
2005 |
Argentinean Championship | B80 Sicilian, Scheveningen |
| 19. S Alonso vs P Lafuente |
| 0-1 | 102 |
2005 |
Mercosur Cup | B87 Sicilian, Fischer-Sozin with ...a6 and ...b5 |
| 20. D Flores vs S Alonso |
| 0-1 | 44 |
2005 |
Argentinean Championship | A57 Benko Gambit |
| 21. D Valerga vs S Alonso |
| 0-1 | 65 |
2005 |
Mercosur Cup | B33 Sicilian |
| 22. F Quiroga vs S Alonso |
| 0-1 | 22 |
2005 |
American Continental Championship | D18 Queen's Gambit Declined Slav, Dutch |
| 23. S Alonso vs F Peralta |
| 0-1 | 29 |
2008 |
Argentine Championship | B07 Pirc |
| 24. C Luconi vs S Alonso |
| 0-1 | 28 |
2008 |
Argentine Championship | D02 Queen's Pawn Game |
| 25. R Sola vs S Alonso |
| 0-1 | 27 |
2008 |
Semi Arg Bs. As. | B30 Sicilian |
