Stadium: Pista 5 Round: 62 Ground: Hardcourt outdoor
| ITF W25 Calvi | 2021/04/11 12:10 | Rebecca Amerio v Mariia Kostiuk | 6-4,6-1 |
| ITF W25 Manacor | 2021/03/09 09:00 | Olga Parres Azcoitia v Mariia Kostiuk | 6-2,6-1 |
| ITF W25 Selva Gardena | 2020/12/13 13:20 | Mariia Kostiuk v Verena Hofer | 3-6,3-6 |
| ITF W15 LPD Gran Canaria | 2020/11/23 10:15 | Mariia Kostiuk v Rebeca Pereira | 1-6,0-6 |
| ITF W15 LPD Gran Canaria | 2020/11/22 09:30 | Mariia Kostiuk v Maria Fernanda Morales | 6-3,6-1 |
| ITF Women Castellon | 2020/11/01 10:30 | Mariia Kostiuk v Maria B Bandera | 3-6,1-6 |
| ITF W15 Platja D'Aro | 2020/10/25 11:00 | Ali Collins v Mariia Kostiuk | 7-5,6-3 |
| ITF W60 Saint Malo | 2020/09/07 10:30 | Mariia Kostiuk v Aubane Droguet | 2-6,1-6 |
| ITF W15 Villena | 2021/02/07 12:30 | Fabienne Gettwart v Maria Garcia Cid | 6-7,7-5,7-10 |
| ITF W15 Madrid | 2020/12/06 13:00 | Maria Garcia Cid v Alba Rey Garcia | 0-6,6-0,6-10 |