| Game |
| Result | Moves |
Year |
Event/Locale | Opening |
| 1. S Christensen vs H S Gretarsson |
| ½-½ | 56 |
2006 |
Politiken Cup | B22 Sicilian, Alapin |
| 2. V Nithander vs H S Gretarsson |
| 0-1 | 67 |
2007 |
Politiken Cup | B60 Sicilian, Richter-Rauzer |
| 3. M Kamali vs H S Gretarsson |
| 0-1 | 29 |
2008 |
EU-ch U16 18th | B48 Sicilian, Taimanov Variation |
| 4. F Steil-Antoni vs H S Gretarsson |
| 0-1 | 42 |
2008 |
Reykjavik Open | B26 Sicilian, Closed, 6.Be3 |
| 5. S D Sigfusson vs H S Gretarsson |
| ½-½ | 40 |
2008 |
Hellir International | B48 Sicilian, Taimanov Variation |
| 6. H Vardanian vs H S Gretarsson |
| ½-½ | 34 |
2008 |
EU-ch U16 18th | B47 Sicilian, Taimanov (Bastrikov) Variation |
| 7. D Bojkov vs H S Gretarsson |
| 1-0 | 55 |
2008 |
Reykjavik Open | B40 Sicilian |
| 8. H Tamazyan vs H S Gretarsson |
| 0-1 | 32 |
2008 |
EU-ch U16 18th | B40 Sicilian |
| 9. A Olsson vs H S Gretarsson |
| 1-0 | 40 |
2008 |
Euro Club Cup | B23 Sicilian, Closed |
| 10. N Grandelius vs H S Gretarsson |
| 1-0 | 26 |
2008 |
EU-ch U16 18th | B48 Sicilian, Taimanov Variation |
| 11. C Jeitz vs H S Gretarsson |
| 1-0 | 60 |
2008 |
Euro Club Cup | B40 Sicilian |
| 12. Galego vs H S Gretarsson |
| 0-1 | 37 |
2009 |
Reykjavik Open | B44 Sicilian |
| 13. N Grandelius vs H S Gretarsson |
 | 1-0 | 32 |
2009 |
Reykjavik Open | B90 Sicilian, Najdorf |
| 14. C Angulo P vs H S Gretarsson |
| 0-1 | 48 |
2010 |
Chess Olympiad | B93 Sicilian, Najdorf, 6.f4 |
| 15. V Bilic vs H S Gretarsson |
| 0-1 | 66 |
2011 |
European Club Cup | B36 Sicilian, Accelerated Fianchetto |
| 16. Areshchenko vs H S Gretarsson |
| 1-0 | 54 |
2011 |
European Club Cup | B32 Sicilian |
| 17. S Thorgeirsson vs H S Gretarsson |
| ½-½ | 73 |
2011 |
Reykjavik Open | B23 Sicilian, Closed |
| 18. Y Kuzubov vs H S Gretarsson |
| ½-½ | 58 |
2012 |
Reykjavik Open | B40 Sicilian |
| 19. A Ashton vs H S Gretarsson |
| 0-1 | 36 |
2012 |
Hastings Chess Congress | B87 Sicilian, Fischer-Sozin with ...a6 and ...b5 |
| 20. N Steinberg vs H S Gretarsson |
| ½-½ | 76 |
2012 |
23rd Czech Open A | B90 Sicilian, Najdorf |
| 21. A Greet vs H S Gretarsson |
| 1-0 | 54 |
2012 |
4NCL 2012/13 | B22 Sicilian, Alapin |
| 22. Velicka vs H S Gretarsson |
| ½-½ | 30 |
2012 |
23rd Czech Open A | B51 Sicilian, Canal-Sokolsky (Rossolimo) Attack |
| 23. C Wagener vs H S Gretarsson |
| 0-1 | 40 |
2012 |
Chess Olympiad | B92 Sicilian, Najdorf, Opocensky Variation |
| 24. K Rjabzev vs H S Gretarsson |
| 0-1 | 57 |
2012 |
23rd Czech Open A | B93 Sicilian, Najdorf, 6.f4 |
| 25. Joseph Atwoli vs H S Gretarsson |
| 0-1 | 26 |
2012 |
Chess Olympiad | B23 Sicilian, Closed |