| ITF W25 Sunderland | 02/26 13:35 | 25 | [366] Emma Raducanu v Elitsa Kostova [195] | 7-5,6-1 | |
| WTA Dubaj | 02/15 11:15 | 44 | [191] Elitsa Kostova v Giulia G-Monticone [149] | 5-7,1-6 | |
| ITF W25 Trnava | 02/13 11:35 | 26 | Irina Khromacheva v Elitsa Kostova | 6-4,6-4 | |
| ITF W25 Trnava | 02/12 15:35 | 25 | Ayline Esina Samardzic v Elitsa Kostova | 1-6,1-6 | |
| ITF W25 Trnava | 02/05 13:50 | 25 | [190] Elitsa Kostova v Andrea Lazaro Garcia [342] | 3-6,3-6 | |
| Australian Open - ženy | 01/14 07:55 | 44 | [194] Elitsa Kostova v Harriet Dart [169] | 4-6,1-6 | |
| WTA Houston | 11/11 16:00 | 24 | [279] Hailey Baptiste v Elitsa Kostova [197] | 6-2,6-4 | |
| ITF W60 Las Vegas | 11/06 17:00 | 25 | [302] Stephanie Wagner v Elitsa Kostova [193] | 7-5,6-2 | |
| ITF W60 Toronto | 11/01 18:05 | 27 | [99] Kirsten Flipkens v Elitsa Kostova [199] | 6-3,6-2 | |
| ITF W60 Toronto | 10/31 16:55 | 26 | [455] Naomi Broady v Elitsa Kostova [199] | 3-6,3-6 | |
| ITF W60 Toronto | 10/30 13:50 | 25 | Melodie Collard v Elitsa Kostova | 2-6,6-4,1-6 | |
| ITF W25 Istanbul | 10/23 09:55 | 26 | Elitsa Kostova v Anna Kubareva | 6-7,6-2,5-7 | |
| ITF W25 Istanbul | 10/22 12:40 | 25 | [199] Elitsa Kostova v Berfu Cengiz [452] | 7-5,6-0 | |
| WTA Moskva | 10/12 16:05 | 45 | [212] Elitsa Kostova v Valentini Grammatikopoulou [230] | 3-6,4-6 | |
| ITF W25 Santa Margherita | 10/05 12:00 | 28 | [211] Elitsa Kostova v Teliana Pereira [487] | 5-7,4-6 | |
| ITF W25 Santa Margherita | 10/04 12:00 | 27 | [358] Carolina Meligeni Rodrigues Alves v Elitsa Kostova [211] | 3-6,4-6 | |
| ITF W25 Santa Margherita | 10/03 12:00 | 26 | [397] Anastasia Detiuc v Elitsa Kostova [211] | 4-6,6-4,1-6 | |
| ITF W25 Santa Margherita | 10/02 14:20 | 25 | Melania Delai v Elitsa Kostova | 0-6,0-6 | |
| ITF W60 Caldas da Rainha | 09/25 12:30 | 25 | [209] Elitsa Kostova v Ylena In-Albon [270] | 4-6,2-6 | |
| ITF W60 Meitar | 09/13 09:00 | 28 | [220] Elitsa Kostova v Katharina Hobgarski [206] | 6-0,3-6,1-6 | |
| ITF W60 Meitar | 09/12 08:10 | 27 | [220] Elitsa Kostova v Quirine Lemoine [247] | 6-2,7-6 | |
| ITF W60 Meitar | 09/11 14:00 | 26 | [220] Elitsa Kostova v Chanel Simmonds [387] | 6-2,6-3 | |
| ITF W60 Meitar | 09/10 12:35 | 25 | [220] Elitsa Kostova v Ilona G Ghioroaie [475] | 6-3,6-0 | |
| ITF W60 Záhřeb | 09/07 09:30 | 27 | [231] Cagla Buyukakcay v Elitsa Kostova [227] | 6-2,6-4 | |
| ITF W60 Záhřeb | 09/05 13:00 | 26 | [227] Elitsa Kostova v Antonia Lottner [195] | 6-2,4-6,7-6 | |
| ITF W60 Záhřeb | 09/04 13:00 | 25 | [227] Elitsa Kostova v Silvia Njiric [483] | 6-4,6-7,6-3 | |
| ITF W25 Bagnatica | 08/30 19:55 | 27 | [227] Elitsa Kostova v Tamara Korpatsch [111] | 7-6,5-7,2-6 | |
| ITF W25 Bagnatica | 08/29 19:00 | 26 | [227] Elitsa Kostova v Tessah Andrianjafitrimo [265] | 6-4,6-4 | |
| ITF W25 Bagnatica | 08/28 10:15 | 25 | [227] Elitsa Kostova v Lara Salden [303] | 3-6,6-4,6-1 | |
| US Open - ženy | 08/20 17:40 | 44 | [228] Elitsa Kostova v Yanina Wickmayer [162] | 5-7,4-6 |