Stadium: Court 1 Round: 25 Ground: Hardcourt indoor
| ITF W25 Lagos | 2021/10/15 11:55 | Antonia Ruzic v Simona Waltert | 6-0,6-4 |
| ITF W25 Lagos | 2021/10/14 14:00 | Jessica Bouzas Maneiro v Simona Waltert | 4-6,4-6 |
| ITF W25 Lagos | 2021/10/13 14:15 | Joanna Garland v Simona Waltert | 5-7,4-6 |
| ITF W25 Loule | 2021/10/08 15:05 | Chloe Paquet v Simona Waltert | 6-0,6-4 |
| ITF W25 Loule | 2021/10/07 14:10 | Joanna Garland v Simona Waltert | 1-6,1-6 |
| ITF W25 Loule | 2021/10/06 13:00 | Maria G Carrasco v Simona Waltert | 6-4,4-6,0-6 |
| ITF W25 Lisbon | 2021/10/01 09:25 | Andrea Lazaro Garcia v Simona Waltert | 6-3,3-6,6-4 |
| ITF W25 Lisbon | 2021/09/30 09:30 | Simona Waltert v Paula Ormaechea | 6-0,4-6,6-2 |
| ITF W25 Cherbourg | 2021/10/06 08:25 | Karen Marthiens v Himari Sato | 6-3,3-6,0-6 |
| ITF W25 Cherbourg | 2021/10/04 08:30 | Fiona Ganz v Karen Marthiens | 6-2,6-1 |
| ITF W25 Cherbourg | 2021/10/03 10:15 | Mariana Galvao Borges v Karen Marthiens | 0-6,1-6 |
| ITF W15 Dijon | 2021/09/14 11:00 | Karen Marthiens v Anna Klasen | 1-6,1-6 |
| ITF W15 Amarante | 2021/07/20 16:00 | Karen Marthiens v Ayla Aksu | 2-6,3-6 |
| ITF W60 Vitoria-Gasteiz | 2021/07/12 10:00 | Laetitia Pulchartova v Karen Marthiens | 7-5,6-4 |
| ITF W60 Vitoria-Gasteiz | 2021/07/11 09:20 | Lilly Elida Haseth v Karen Marthiens | 4-6,6-4,7-10 |
| ITF W25 Perigueux | 2021/06/22 08:00 | Karen Marthiens v Guiomar Maristany Zuleta De Reales | 3-6,0-6 |