| ITF Women Prokuplje | 2018/07/12 08:40 | Katarina Kostic v Barbara Bonic | 0-6,4-6 |
| ITF Women Prokuplje | 2018/07/11 09:00 | Kiara Cvetkovic v Katarina Kostic | 2-6,6-2,2-6 |
| ITF Women Prokuplje Qual | 2018/07/09 07:00 | Costanza Traversi v Katarina Kostic | 4-6,3-6 |
| ITF Women Prokuplje Qual | 2018/06/30 07:00 | Katarina Kostic v Andrijana Stoilkovic | 2-6,2-6 |
| ITF Women Maribor | 2018/06/13 08:00 | Nina Alibalic v Katarina Kostic | 7-5,6-3 |
| ITF Women Maribor Qual | 2018/06/11 08:40 | Katarina Kostic v Emily Morton | 6-2,6-2 |
| ITF Women Maribor Qual | 2018/06/10 11:35 | Taro Keens v Katarina Kostic | 2-6,1-6 |
| ITF Women Maribor Qual | 2018/06/09 07:30 | Ayline Esina Samardzic v Katarina Kostic | 5-7,2-6 |