| 1. Round | 01/03/2021 | Seongnam FC | - | Jeju United | 0:0 | ||||
| 2. Round | 06/03/2021 | Jeju United | - | Jeonbuk FC | 1:1 | ||||
| 3. Round | 09/03/2021 | Jeju United | - | Pohang Steelers | 1:0 | ||||
| 4. Round | 13/03/2021 | Daegu FC | - | Jeju United | 1:1 | ||||
| 5. Round | 16/03/2021 | Ulsan Hyundai FC | - | Jeju United | 0:0 | ||||
| 13. Round | 02/05/2021 | Jeonbuk FC | - | Jeju United | 1:1 | ||||
| 14. Round | 08/05/2021 | Jeju United | - | Suwon FC | 1:3 | ||||
| 18. Round | 22/05/2021 | Jeju United | - | Seongnam FC | 2:2 | ||||
| 19. Round | 29/05/2021 | Jeju United | - | Ulsan Hyundai FC | 1:2 |
Poland