| WTA Moscow Qual | 07/23 09:10 | 64 | [415] Anastasia Gasanova v Valentini Grammatikopoulou [179] | 4-6,3-6 | |
| WTA Moscow Qual | 07/22 07:00 | 45 | [206] Jessica Pieri v Valentini Grammatikopoulou [179] | 2-6,4-6 | |
| ITF Women Getxo | 07/10 09:35 | 25 | [175] Valentini Grammatikopoulou v Montserrat Gonzalez [373] | 6-4,4-6,4-6 | |
| ITF Women Denain | 07/07 12:00 | 28 | [175] Valentini Gram'lou v Valeriya Strakhova [355] | 6-3,4-6,4-6 | |
| ITF Women Denain | 07/06 10:45 | 27 | [175] Valentini Gram'lou v Anna Danilina [497] | 6-4,7-6 | |
| ITF Women Denain | 07/05 12:45 | 26 | [175] Valentini Gram'lou v Alice Rame [490] | 7-6,2-6,6-2 | |
| ITF Women Denain | 07/04 08:30 | 25 | Valentini Gram'lou v Anna-Giulia Remondina | 7-6,6-7,6-2 | |
| Wimbledon Women Qual | 06/26 14:40 | 44 | [139] Sofya Zhuk v Valentini Grammatikopoulou [174] | 6-3,6-2 | |
| WTA Hertogenbosch | 06/12 09:00 | 25 | [179] Valentini Grammatikopoulou v Aleksandra Krunic [55] | 1-6,0-6 | |
| WTA Hertogenbosch Qual | 06/10 09:00 | 64 | [174] Valentini Grammatikopoulou v Katarzyna Piter [371] | 6-4,6-4 | |
| WTA Hertogenbosch Qual | 06/09 09:20 | 45 | Valentini Grammatikopoulou v Dewi Dijkman | 6-3,6-1 | |
| French Open Women Qual | 05/24 09:30 | 45 | [158] Anna Kalinskaya v Valentini Grammatikopoulou [176] | 3-6,6-1,6-2 | |
| French Open Women Qual | 05/22 13:55 | 44 | [176] Valentini Grammatikopoulou v Sofya Zhuk [136] | 6-1,1-6,7-6 | |
| ITF Women Saint Gaudens | 05/18 12:00 | 27 | [313] Quirine Lemoine v Valentini Grammatikopoulou [174] | 6-2,6-4 | |
| ITF Women Saint Gaudens | 05/17 15:00 | 26 | [174] Valentini Grammatikopoulou v Richel Hogenkamp [121] | 7-6,6-1 | |
| ITF Women Saint Gaudens | 05/16 08:00 | 25 | [174] Valentini Grammatikopoulou v Kimberly Birrell [353] | 4-6,7-5,6-2 | |
| ITF Women Khimki | 05/02 10:30 | 26 | [175] Valentini Gramma'poulou v Julia Glushko [303] | 4-6,6-7 | |
| ITF Women Khimki | 05/01 09:45 | 25 | Valentini Gramma'poulou v Angelina Gabueva | 6-7,7-6,6-4 | |
| 2018 Fed Cup | 04/21 08:00 | 28 | [171] Valentini Gramma'poulou v Eleonora Molinaro [450] | 3-6,6-3,4-6 | |
| 2018 Fed Cup | 04/20 08:00 | - | Clara Tauson v Valentini Grammatikopoulou | 7-6,6-7,0-6 | |
| 2018 Fed Cup | 04/19 08:00 | - | Dona Abo Habaga v Valentini Gram'lou | 2-6,3-6 | |
| WTA Bogota | 04/12 15:00 | 26 | [183] Valentini Gramma'poulou v Johanna Larsson [73] | 6-4,4-6,4-6 | |
| WTA Bogota | 04/11 15:00 | 25 | [183] Valentini Gramma'poulou v Miyu Kato [138] | 5-7,6-4,6-4 | |
| WTA Bogota Qual | 04/08 17:15 | - | Valentini Grammatikopoulou v Irina Khromacheva | 7-6,7-6 | |
| WTA Bogota Qual | 04/07 17:15 | 45 | [185] Valentini Grammatikopoulou v Tereza Mrdeza [230] | 4-6,6-4,6-3 | |
| WTA Monterrey | 04/03 16:00 | 25 | [185] Valentini Gramma'poulou v Jana Fett [109] | 0-6,2-6 | |
| WTA Monterrey Qual | 04/02 16:00 | 54 | [185] Valentini Grammatikopoulou v Conny Perrin [181] | 6-2,6-2 | |
| WTA Monterrey Qual | 04/01 18:00 | 46 | [193] Priscilla Hon v Valentini Grammatikopoulou [187] | 6-7,3-6 | |
| WTA Monterrey Qual | 03/31 16:00 | 45 | [226] Tereza Mrdeza v Valentini Grammatikopoulou [187] | 3-6,6-2,2-6 | |
| ITF Women Shenzhen Qual | 03/11 04:05 | 46 | Valentini Grammatikopoulou v Ivana Jorovic | 3-6,1-6 |