| 18. Jornada | 12.02.2021 | Hajduk Split II | - | NK Opatija | 2:2 | ||||
| 19. Jornada | 20.02.2021 | NK Opatija | - | NK Sesvete | 1:0 | ||||
| 20. Jornada | 27.02.2021 | NK Solin | - | NK Opatija | 1:1 | ||||
| 21. Jornada | 06.03.2021 | NK Opatija | - | NK Rudeš | 0:0 | ||||
| 22. Jornada | 14.03.2021 | HNK Cibalia | - | NK Opatija | 2:0 | ||||
| 23. Jornada | 20.03.2021 | NK Opatija | - | NK Dubrava | 2:1 | ||||
| 24. Jornada | 02.04.2021 | HNK Orijent Rijeka | - | NK Opatija | 4:1 | ||||
| 26. Jornada | 17.04.2021 | NK Osijek II | - | NK Opatija | 1:0 | ||||
| 27. Jornada | 21.04.2021 | NK Opatija | - | NK Junak Sinj | 1:0 | ||||
| 28. Jornada | 24.04.2021 | NK Dugopolje | - | NK Opatija | 0:0 | ||||
| 25. Jornada | 28.04.2021 | NK Opatija | - | Hrvatski Dragovoljac | 0:0 | ||||
| 29. Jornada | 01.05.2021 | NK Opatija | - | NK Međimurje | 1:1 |  |
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| 30. Jornada | 07.05.2021 | NK Inter Zaprešić | - | NK Opatija | 3:0 | ||||
| 31. Jornada | 12.05.2021 | NK Opatija | - | NK Kustošija | 0:0 | ||||
| 32. Jornada | 16.05.2021 | NK Croatia Zmijavci | - | NK Opatija | 1:3 |  |
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| 33. Jornada | 23.05.2021 | Dinamo Zagreb II | - | NK Opatija | 2:2 | |
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| 34. Jornada | 29.05.2021 | NK Opatija | - | NK BSK Bijelo Brdo | 2:2 | |
Croacia