Stadium: Court 4 Round: 25 Ground: Clay
| ITF W25 Kyiv | 2021/07/21 08:55 | Poznikhirenko, Ganna v Kostenko, L. | 6-1,6-0 |
| ITF - W15 Antalya | 2021/07/01 06:25 | Claudia Hoste Ferrer v Kostenko, L. | 6-4,3-6,7-6 |
| ITF - W15 Antalya | 2021/06/29 11:25 | Ani Vangelova v Kostenko, L. | 3-6,3-6 |
| ITF - W15 Antalya | 2021/06/10 08:50 | Lukacs, Vanda v Kostenko, L. | 6-1,6-1 |
| ITF - W15 Antalya | 2021/06/09 11:35 | Martinich, Ivania v Kostenko, L. | 6-2,2-6,2-6 |
| ITF - W15 Antalya | 2021/06/03 07:30 | Federica Bilardo v Kostenko, L. | 7-5,6-2 |
| ITF - W15 Antalya | 2021/06/02 08:25 | Kostenko, L. v Ng, Taylor | 6-4,6-2 |
| ITF - W15 Sharm El Sheikh | 2021/04/07 07:00 | Kostenko, L. v Andre Lukosiute | 2-6,4-6 |