| 10. Round | 17/10/2020 | NK Junak Sinj | - | NK Opatija | 0:2 | ||||
| 12. Round | 30/10/2020 | NK Međimurje | - | NK Opatija | 3:0 | ||||
| 11. Round | 14/11/2020 | NK Opatija | - | NK Dugopolje | 2:1 | ||||
| 14. Round | 21/11/2020 | NK Kustošija | - | NK Opatija | 2:1 | ||||
| 13. Round | 25/11/2020 | NK Opatija | - | NK Inter Zaprešić | 3:2 |  |
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| 16. Round | 05/12/2020 | NK Opatija | - | Dinamo Zagreb II | 2:1 | ||||
| 19. Round | 20/02/2021 | NK Opatija | - | NK Sesvete | 1:0 | ||||
| 21. Round | 06/03/2021 | NK Opatija | - | NK Rudeš | 0:0 | ||||
| 22. Round | 14/03/2021 | HNK Cibalia | - | NK Opatija | 2:0 | ||||
| 23. Round | 20/03/2021 | NK Opatija | - | NK Dubrava | 2:1 |
Croatia