| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. Enrique Contessotto vs S Mareco |
| 1-0 | 31 |
2001 |
CEFA IRT-4 | C50 Giuoco Piano |
| 2. E Scarella vs S Mareco |
| 0-1 | 37 |
2005 |
American Continental | E97 King's Indian |
| 3. D Alzate vs S Mareco |
| 1-0 | 25 |
2005 |
American Continental Championship | D02 Queen's Pawn Game |
| 4. S Mareco vs M Mosquera |
| ½-½ | 19 |
2005 |
American Continental Championship | B92 Sicilian, Najdorf, Opocensky Variation |
| 5. A Bachmann vs S Mareco |
| ½-½ | 80 |
2005 |
American Continental Championship | B30 Sicilian |
| 6. S Mareco vs C Dolezal |
| ½-½ | 40 |
2005 |
American Continental Championship | B00 Uncommon King's Pawn Opening |
| 7. S Mareco vs G Garcia |
| ½-½ | 21 |
2005 |
American Continental Championship | A25 English |
| 8. G Soppe vs S Mareco |
| ½-½ | 46 |
2005 |
American Continental Championship | E63 King's Indian, Fianchetto, Panno Variation |
| 9. P Lafuente vs S Mareco |
| 0-1 | 24 |
2005 |
American Continental Championship | D07 Queen's Gambit Declined, Chigorin Defense |
| 10. Le Quang Liem vs S Mareco |
| ½-½ | 72 |
2006 |
World Junior Championship | A45 Queen's Pawn Game |
| 11. S Mareco vs B Grachev |
 | 0-1 | 32 |
2006 |
World Junior Championship | A07 King's Indian Attack |
| 12. S Mareco vs S Shoker |
| 1-0 | 41 |
2006 |
World Junior Championship | B07 Pirc |
| 13. Zhou Jianchao vs S Mareco |
| ½-½ | 55 |
2006 |
World Junior Championship | E15 Queen's Indian |
| 14. S Alavi vs S Mareco |
| ½-½ | 28 |
2006 |
World Junior Championship | C24 Bishop's Opening |
| 15. S Mareco vs E Romanov |
| 1-0 | 29 |
2006 |
World Junior Championship | C92 Ruy Lopez, Closed |
| 16. S Mareco vs T H Toufighi |
| 1-0 | 40 |
2006 |
World Junior Championship | C19 French, Winawer, Advance |
| 17. S Mareco vs D Baramidze |
| ½-½ | 19 |
2006 |
World Junior Championship | B90 Sicilian, Najdorf |
| 18. S Mareco vs F Corrales Jimenez |
| 0-1 | 49 |
2006 |
World Junior Championship | A25 English |
| 19. S Mareco vs L Fusco |
| ½-½ | 34 |
2007 |
III South American Ch U20 | E63 King's Indian, Fianchetto, Panno Variation |
| 20. S Mareco vs G Needleman |
| 1-0 | 51 |
2007 |
III South American Ch U20 | A70 Benoni, Classical with 7.Nf3 |
| 21. S Mareco vs L Duarte |
| ½-½ | 26 |
2007 |
zt 2.5 m | A57 Benko Gambit |
| 22. A Hilario Ta Fier vs S Mareco |
 | 0-1 | 33 |
2007 |
III South American Ch U20 | C11 French |
| 23. Le Rossi vs S Mareco |
| 0-1 | 64 |
2007 |
III South American Ch U20 | C56 Two Knights |
| 24. S Mareco vs E Cordova |
| 1-0 | 64 |
2007 |
III South American Ch U20 | E43 Nimzo-Indian, Fischer Variation |
| 25. S Mareco vs D Di Berardino |
| ½-½ | 22 |
2007 |
III South American Ch U20 | B90 Sicilian, Najdorf |