| UTR Pro Tennis Series Pazardzhik Women | 2021/05/11 10:00 | Shkumbova, Mirela v Kostova, Elitsa | 0-6,1-6 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/06 10:00 | Shkumbova, Mirela v Kostova, Elitsa | 1-6,0-6 |
| UTR Pro Tennis Series Plovdiv Women | 2021/12/13 12:00 | Mariya Vyshkina v Shkumbova, Mirela | 1-6,3-6 |
| ITF W15 Sozopol | 2021/09/14 07:00 | Defne Cirpanli v Shkumbova, Mirela | 6-1,6-1 |
| ITF W15 Sozopol | 2021/09/13 10:30 | Ekaterina Kuznetsova v Shkumbova, Mirela | 5-7,4-6 |
| ITF Women Varna | 2021/09/05 05:30 | Gvozdenovic, Sara v Shkumbova, Mirela | 4-6,6-2,10-7 |
| UTR Pro Tennis Series Sofia Women | 2021/09/01 08:00 | Shkumbova, Mirela v Peeva, Stela | 1-6,4-6 |
| UTR Pro Tennis Series Sofia Women | 2021/08/31 09:30 | Shkumbova, Mirela v Kolar, Nastja | 2-6,6-2,1-5 |
| UTR Pro Tennis Series Sofia Women | 2021/08/29 13:30 | Maja Radenkovic v Shkumbova, Mirela | 6-3,4-6,5-2 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/13 06:00 | Shkumbova, Mirela v Ruseva, Nikol | 6-4,5-2 |
| UTR Pro Tennis Series Barcelona Women | 2021/11/07 12:20 | Kostova, Elitsa v Zlochova, Zuzana | 3-6,5-7 |
| UTR Pro Tennis Series Barcelona Women | 2021/11/06 09:30 | Kostova, Elitsa v Lantigua de La Nuez, Ana | 6-0,6-1 |
| UTR Pro Tennis Series Barcelona Women | 2021/11/05 15:15 | Kostova, Elitsa v Valeria Avdeeva | 6-1,6-2 |
| UTR Pro Tennis Series Barcelona Women | 2021/11/04 11:30 | Kostova, Elitsa v Nina Ugrelidze | 4-6,6-1,6-0 |
| UTR Pro Tennis Series Barcelona Women | 2021/11/03 10:00 | Agustina Chlpac v Kostova, Elitsa | 3-6,0-6 |
| UTR Pro Tennis Series Barcelona Women | 2021/11/02 12:30 | Lucia Aranda Arcas v Kostova, Elitsa | 6-4,4-6,1-5 |
| WTA Belgrade | 2021/07/27 14:50 | Kostova, Elitsa v Arantxa Rus | 1-6,0-6 |
| ITF W60 Biarritz | 2021/07/14 09:30 | Kostova, Elitsa v Estelle Cascino | 4-6,3-6 |