| 3. Round | 22/08/1998 | Beşiktaş | - | Gaziantepspor | 1:1 | ||||
| 4. Round | 29/08/1998 | Gaziantepspor | - | MKE Ankaragücü | 1:0 |  |
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| 5. Round | 12/09/1998 | Antalyaspor | - | Gaziantepspor | 3:1 | ||||
| 6. Round | 19/09/1998 | Gaziantepspor | - | Dardanelspor | 1:0 | ||||
| 10. Round | 30/10/1998 | İstanbulspor AŞ | - | Gaziantepspor | 0:0 | ||||
| 11. Round | 07/11/1998 | Gaziantepspor | - | Erzurumspor (1968-2015) | 3:0 | ||||
| 12. Round | 13/11/1998 | Fenerbahçe | - | Gaziantepspor | 4:0 | ||||
| 13. Round | 21/11/1998 | Gaziantepspor | - | Gençlerbirliği | 2:2 | ||||
| 14. Round | 26/11/1998 | Adanaspor | - | Gaziantepspor | 3:1 | ||||
| 16. Round | 12/12/1998 | Karabükspor | - | Gaziantepspor | 2:6 | |
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| 19. Round | 06/02/1999 | Sakaryaspor | - | Gaziantepspor | 6:2 | |
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| 29. Round | 23/04/1999 | Gaziantepspor | - | Fenerbahçe | 2:2 | ||||
| 33. Round | 21/05/1999 | Gaziantepspor | - | Karabükspor | 4:2 | |
Turkey