Stadium: Center Court Round: 45 Ground: Carpet indoor
| ITF W25 Altenkirchen | 2021/02/14 12:30 | Gerlach, Katharina v Shiho Akita | 6-0,5-7,10-8 |
| ITF W60 Rome GA | 2021/01/28 00:10 | Irene Burillo Escorihuela v Gerlach, Katharina | 3-6,6-2,6-1 |
| ITF W25 Fujairah | 2021/01/19 09:45 | Gerlach, Katharina v Xinyu Wang | 1-6,2-6 |
| ITF W25 Fujairah | 2021/01/18 07:35 | Gerlach, Katharina v Semenistaja, Marija | 6-0,6-0 |
| Open d'Australie - Femmes | 2021/01/12 13:25 | Gerlach, Katharina v Hibi, Mayo | 3-6,4-6 |
| Open d'Australie - Femmes | 2021/01/11 12:55 | Voegele, Stefanie v Gerlach, Katharina | 3-6,4-6 |
| ITF W25 Selva Gardena | 2020/12/15 16:00 | Tena Lukas v Gerlach, Katharina | 7-5,7-6 |
| German Championship Women | 2020/12/10 12:00 | Gerlach, Katharina v Mara Guth | 5-7,6-4,2-6 |
| ITF W25 Altenkirchen | 2021/02/14 11:00 | Selina Dal v Simona Waltert | 3-6,2-6 |
| Grenoble, Singles Qualifying W-ITF-FRA-04A | 2021/02/08 09:20 | Zimmermann, Kimberley v Simona Waltert | 6-4,6-4 |
| Grenoble, Singles Qualifying W-ITF-FRA-04A | 2021/02/07 10:05 | Amandine Monnot v Simona Waltert | 3-6,3-6 |
| ITF - W15 Manacor | 2021/01/31 11:00 | Simona Waltert v Yvonne Cavalle-Reimers | 6-2,7-6 |
| ITF - W15 Manacor | 2021/01/30 12:05 | Simona Waltert v Shiho Akita | 6-3,6-4 |
| ITF - W15 Manacor | 2021/01/29 10:00 | Simona Waltert v Guttierez Carrasco, Maria | 7-6,6-4 |
| ITF - W15 Manacor | 2021/01/28 12:10 | Simona Waltert v Noemi Basiletti | 6-3,6-3 |
| ITF - W15 Manacor | 2021/01/27 09:30 | Simona Waltert v Oksana Selekhmeteva | 6-4,6-2 |