Stadium: Court 3 Round: 44
| ITF Women Szekesfehervar | 2018/09/01 08:00 | Malatinska, Justyna v Beberechi, Andreia | 6-3,4-6,6-3 |
| ITF Women Vrnjacka Banja | 2018/08/18 09:30 | Malatinska, Justyna v Joelle Lilly Sophie Steur | 6-7,4-6 |
| ITF Women Warsaw Qual | 2018/08/04 07:00 | Sumova, Diana v Malatinska, Justyna | 6-1,3-6,6-1 |
| ITF Women Sandelfjord | 2018/07/25 09:00 | Malatinska, Justyna v Ponomar, Lisa | 3-6,2-6 |
| ITF Women Sandelfjord | 2018/07/24 11:40 | Elde, Emilie v Malatinska, Justyna | 4-6,3-6 |
| ITF Women Baja | 2018/07/17 08:00 | Malatinska, Justyna v Guglielminotti, Sara | 2-6,3-6 |
| ITF Women Baja | 2018/07/16 08:00 | Potrc, Moni v Malatinska, Justyna | 4-6,1-6 |
| ITF Women Jablonec Nad Nisou | 2018/06/26 08:00 | Malatinska, Justyna v Krizova, Katerina | 4-6,4-6 |
| ITF Women Vrnjacka Banja | 2018/08/19 10:00 | Kostic, Katarina v Zupancic, Nika | 3-6,6-4,2-6 |
| Prokuplje, Singles W-WITF-SRB-02A | 2018/07/12 08:40 | Kostic, Katarina v Bonic, Barbara | 0-6,4-6 |
| Prokuplje, Singles W-WITF-SRB-02A | 2018/07/11 09:00 | Kiara Cvetkovic v Kostic, Katarina | 2-6,6-2,2-6 |
| ITF Women Prokuplje Qual | 2018/07/09 07:00 | Costanza Traversi v Kostic, Katarina | 4-6,3-6 |
| ITF Women Prokuplje Qual | 2018/06/30 07:00 | Kostic, Katarina v Stoilkovic, Andrijana | 2-6,2-6 |
| ITF Women Maribor | 2018/06/13 08:00 | Nina Alibalic v Kostic, Katarina | 7-5,6-3 |
| ITF Women Maribor Qual | 2018/06/11 08:40 | Kostic, Katarina v Morton, Emily | 6-2,6-2 |
| ITF Women Maribor Qual | 2018/06/10 11:35 | Keens, Taro v Kostic, Katarina | 2-6,1-6 |