| ITF Women Monastir | 2018/10/21 10:30 | Sama, Sathwika v Sonnekus-Williams, Olivia | 6-0,6-3 |
| ITF Women Badenweiler | 2018/09/03 09:00 | Ramirez, Evita v Sonnekus-Williams, Olivia | 6-0,6-2 |
| ITF Women Woking Qual | 2018/07/30 10:00 | Sonnekus-Williams, Olivia v Arbuthnott, Emily | 1-6,1-6 |
| ITF Women Les Contamines | 2018/07/22 08:00 | Lommer, Chiara v Sonnekus-Williams, Olivia | 6-2,6-2 |
| ITF Women Dijon | 2018/07/14 12:45 | Sonnekus-Williams, Olivia v Maneva Rakotomalala | 3-6,0-6 |
| ITF Women Verbier Qual | 2018/06/24 09:00 | Jessie Aney v Sonnekus-Williams, Olivia | 6-3,6-3 |
| ITF Women Verbier Qual | 2018/06/23 08:00 | Sonnekus-Williams, Olivia v Fiacan, Maria Michaela | 6-4,6-2 |
| ITF Women Klosters | 2018/06/17 08:00 | Tayisiya Morderger v Sonnekus-Williams, Olivia | 6-0,6-0 |
| ITF Women Monastir | 2018/10/23 09:00 | Jansen Figueras, Helena v Drozd Pereira, Erika | 4-6,4-6 |
| ITF Women Monastir | 2018/09/17 08:30 | Jansen Figueras, Helena v Emmanuelle Girard | 3-6,3-6 |
| ITF Women Monastir | 2018/09/12 09:00 | Jansen Figueras, Helena v Brune Olsen, Astrid Wanja | 4-6,4-6 |
| ITF Women Monastir | 2018/09/04 09:00 | Jansen Figueras, Helena v Victoria Muntean | 4-6,0-6 |
| ITF Women Monastir | 2018/09/03 09:00 | Jansen Figueras, Helena v Kalava, Iikhitha | 6-1,6-3 |
| ITF Women Wanfercee-Baulet | 2018/08/19 10:30 | Jansen Figueras, Helena v Puig Caballero, Blanca | 6-7,2-6 |
| ITF Women Dijon | 2018/07/15 08:30 | Fahey, Katharine v Jansen Figueras, Helena | 6-0,6-0 |
| ITF Women Dijon | 2018/07/14 10:30 | Gheziel, Myriam v Jansen Figueras, Helena | 7-6,3-6,3-6 |