| 2. Round | 15/08/1998 | İstanbulspor AŞ | - | Samsunspor | 2:1 | ||||
| 3. Round | 21/08/1998 | İstanbulspor AŞ | - | Karabükspor | 3:0 | ||||
| 5. Round | 10/09/1998 | Trabzonspor | - | İstanbulspor AŞ | 0:0 | ||||
| 8. Round | 16/10/1998 | İstanbulspor AŞ | - | MKE Ankaragücü | 1:4 | ||||
| 9. Round | 23/10/1998 | Antalyaspor | - | İstanbulspor AŞ | 2:3 | ||||
| 10. Round | 30/10/1998 | İstanbulspor AŞ | - | Gaziantepspor | 0:0 |  |
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| 11. Round | 07/11/1998 | Altay Izmir | - | İstanbulspor AŞ | 2:1 | ||||
| 12. Round | 14/11/1998 | İstanbulspor AŞ | - | Bursaspor | 2:3 | ||||
| 13. Round | 20/11/1998 | Kocaelispor | - | İstanbulspor AŞ | 0:1 | ||||
| 14. Round | 27/11/1998 | İstanbulspor AŞ | - | Dardanelspor | 1:1 | ||||
| 15. Round | 04/12/1998 | Erzurumspor (1968-2015) | - | İstanbulspor AŞ | 2:4 | ||||
| 16. Round | 12/12/1998 | Fenerbahçe | - | İstanbulspor AŞ | 2:0 |
Turkey