| ITF W15 Sibenik | 2021/05/25 08:00 | Rossi, Federica v Rittberger, Sabrina | 6-3,6-0 |
| ITF W15 Sibenik | 2021/05/24 08:00 | Rittberger, Sabrina v Lisa-Marie Rioux | 7-5,6-4 |
| ITF W15 Sibenik | 2021/05/17 09:25 | Rittberger, Sabrina v Victoria Borodulina | 6-3,5-7,4-10 |
| ITF W15 Sibenik | 2021/05/16 07:30 | Lacasse, Raphaelle v Rittberger, Sabrina | 4-6,7-5,4-10 |
| UTR Pro Tennis Series Barcelona Women | 2021/02/13 12:00 | Rittberger, Sabrina v Alice Tubello | 2-6,2-6 |
| UTR Pro Tennis Series Barcelona Women | 2021/02/12 12:30 | Suvrijn, Jade v Rittberger, Sabrina | 6-0,1-6,6-3 |
| UTR Pro Tennis Series Barcelona Women | 2021/02/11 09:00 | Irina Maria Bara v Rittberger, Sabrina | 6-4,6-1 |
| UTR Pro Tennis Series Barcelona Women | 2021/02/09 09:30 | Atucha Gomez, Ainhoa v Rittberger, Sabrina | 6-2,3-4 |
| German Championship Women | 2021/12/06 09:00 | Charlotte Keitel v Anna Linn Puls | 6-4,7-6 |
| German Championship Women | 2021/12/05 13:00 | Nagel, Hannah v Charlotte Keitel | 6-4,3-6,0-0 |