| ITF W25 Istanbul | 10/26 08:45 | 54 | [266] Valentini Grammatikopoulou v Ekaterina Yashina [249] | 2-6,6-4,10-8 | |
| ITF W25 Cherbourg | 10/12 10:40 | 54 | [479] Suzan Lamens v Valentini Grammatikopoulou [266] | 6-3,6-2 | |
| ITF W25 Cherbourg | 10/11 14:00 | 54 | Sada Nahimana v Valentini Grammatikopoulou | 5-7,1-6 | |
| ITF W25 Prerov | 09/26 08:55 | 28 | [297] Grace Min v Valentini Grammatikopoulou [274] | 6-2,6-3 | |
| ITF W25 Prerov | 09/25 10:25 | 27 | [274] Valentini Grammatikopoulou v Suzan Lamens [316] | 6-3,6-2 | |
| ITF W25 Prerov | 09/24 08:00 | 26 | [313] Elizabeth Halbauer v Valentini Grammatikopoulou [274] | 0-6,3-6 | |
| ITF W25 Prerov | 09/22 12:25 | 25 | Valentini Grammatikopoulou v Anna Siskova | 6-4,6-2 | |
| ITF W25 Zagreb | 09/17 12:00 | 26 | [273] Valentini Grammatikopoulou v Andreea Amalia Rosca [407] | 5-7,6-1,3-6 | |
| ITF W25 Zagreb | 09/15 10:00 | 25 | [169] Allie Kiick v Valentini Grammatikopoulou [273] | Retired | |
| ITF W25 Figueira Da Foz | 09/10 11:30 | 26 | [367] Maia Lumsden v Valentini Grammatikopoulou [297] | 6-1,6-2 | |
| ITF W25 Figueira Da Foz | 09/09 11:00 | 25 | [389] Francisca Jorge v Valentini Grammatikopoulou [297] | 1-6,1-6 | |
| WTA Prague | 09/03 12:50 | 26 | [297] Valentini Grammatikopoulou v Anna K. Schmiedlova [182] | 3-6,0-6 | |
| WTA Prague | 09/02 12:05 | 25 | [297] Valentini Grammatikopoulou v Robin Anderson [198] | 3-6,6-4,6-3 | |
| WTA Prague | 09/01 08:00 | 24 | [153] Martina Trevisan v Valentini Grammatikopoulou [297] | 2-6,1-6 | |
| WTA Prague | 08/30 16:25 | 24 | [297] Valentini Grammatikopoulou v Nuria Parrizas-Diaz [219] | 6-4,6-1 | |
| ITF W25 Olimpia | 03/12 19:00 | - | Valentini Grammatikopoulou v Szabó D. Dorka | View | |
| ITF W25 Olimpia | 03/11 13:00 | 25 | [300] Valentini Grammatikopoulou v Karin Kennel [419] | 2-6,7-6,7-6 | |
| ITF W25 Moszkva | 02/28 10:45 | 27 | Valentini Grammatikopoulou v Taisya Pachkaleva | 6-7,4-6 | |
| ITF W25 Moszkva | 02/27 10:40 | 26 | [306] Valentini Grammatikopoulou v Vlada Koval [397] | 6-3,6-3 | |
| ITF W25 Moszkva | 02/26 13:20 | 25 | [306] Valentini Grammatikopoulou v Valeriya Strakhova [372] | 3-6,6-3,6-3 | |
| ITF W25 Grenoble | 02/12 10:25 | 25 | [218] Harmony Tan v Valentini Grammatikopoulou [302] | 5-7,6-1,6-3 | |
| 2020 Fed Kupa | 02/08 10:55 | - | [165] Isabella Shinikova v Valentini Grammatikopoulou [301] | 6-3,6-1 | |
| 2020 Fed Kupa | 02/06 13:55 | 2 | Sinja Kraus v Valentini Grammatikopoulou | 4-6,4-6 | |
| 2020 Fed Kupa | 02/05 13:55 | 1 | Elena Malygina v Valentini Grammatikopoulou | 4-6,6-4,6-7 | |
| ITF W25 Kazan | 01/25 09:50 | 28 | [278] Dejana Radanovic v Valentini Grammatikopoulou [305] | 6-4,3-6,7-6 | |
| ITF W25 Kazan | 01/24 07:00 | 27 | Taisya Pachkaleva v Valentini Grammatikopoulou | 4-6,6-3,3-6 | |
| ITF W25 Kazan | 01/23 07:00 | 26 | [458] Vivian Heisen v Valentini Grammatikopoulou [305] | 2-6,1-6 | |
| ITF W25 Kazan | 01/21 12:55 | 25 | [381] Valeriya Yushchenko v Valentini Grammatikopoulou [305] | 5-7,6-4,5-7 | |
| WTA Houston | 11/11 17:15 | 24 | [284] Valentini Grammatikopoulou v Eugenie Bouchard [220] | 6-7,4-6 | |
| ITF W60 Colina | 11/07 18:15 | 26 | [215] Elisabetta Cocciaretto v Valentini Gram'lou [265] | 7-5,6-3 |