| UTR Pro Tennis Series Pazardzhik Women | 2021/05/09 08:30 | Kostova, Elitsa v Ogescu, Simona | 7-6,6-2 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/08 09:00 | Kostova, Elitsa v Shalamanova, Daria | 6-4,3-6,6-1 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/07 10:00 | Doroteja Petrovic v Kostova, Elitsa | 1-6,0-6 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/06 10:00 | Shkumbova, Mirela v Kostova, Elitsa | 1-6,0-6 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/04 11:30 | Ralitsa Alexandrova v Kostova, Elitsa | 2-6,0-6 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/03 08:30 | Kostova, Elitsa v Ani Vangelova | 6-1,5-0 |
| ITF W60 Bellinzona | 2021/04/05 13:20 | Turati, Bianca v Kostova, Elitsa | 6-4,6-4 |
| ITF W25 Dubai | 2021/04/01 06:25 | Kostova, Elitsa v Hatouka, Yuliya | 2-6,5-7 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/08 06:00 | Ruseva, Nikol v Trencheva, Elena | 6-4,6-3 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/06 08:30 | Trencheva, Elena v Yoanna Radulova | 4-6,7-6,0-5 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/05 13:30 | Trencheva, Elena v Julia Terziyska | 2-6,1-6 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/04 10:00 | Trencheva, Elena v Katerina Dimitrova | 3-6,0-6 |
| UTR Pro Tennis Series Pazardzhik Women | 2021/05/03 07:00 | Trencheva, Elena v Gebriela Mihaylova | 0-6,3-5 |
| ITF W15 Pazardzhik | 2020/10/26 11:00 | Trencheva, Elena v Draskovic, Anja | 4-6,5-7 |
| ITF Women Varna | 2020/09/07 11:30 | Trencheva, Elena v Chantal Sauvant | 5-7,2-6 |
| ITF - W15 Héraklion | 2020/03/08 08:30 | Trencheva, Elena v Viglianisi, Alice | 6-4,5-7,3-10 |