Stadium: Court 2 Round: 25 Ground: Clay
| WTA Hamburg | 2021/07/05 08:00 | Kucova, Kristina v Stephanie Wagner | 6-1,4-6,6-4 |
| ITF W25 The Hague | 2021/07/02 09:30 | Hogenkamp, Richel v Stephanie Wagner | 6-4,3-6,6-2 |
| ITF W25 The Hague | 2021/07/01 13:45 | Suzan Lamens v Stephanie Wagner | 2-6,6-4,4-6 |
| ITF W25 The Hague | 2021/06/30 10:00 | Stephanie Wagner v Cagla Buyukakcay | 6-4,6-2 |
| ITF W25 Liepaja | 2021/05/26 10:25 | Stephanie Wagner v Ekaterina Makarova | 6-2,6-7,3-6 |
| ITF W25 Platja D’Aro | 2021/05/22 11:00 | Rebeka Masarova v Stephanie Wagner | 6-4,7-5 |
| ITF W25 Platja D’Aro | 2021/05/21 14:00 | Stephanie Wagner v Carlota Martinez Cirez | 3-6,7-5,7-5 |
| ITF W25 Platja D’Aro | 2021/05/20 08:55 | Stephanie Wagner v Andreea Prisacariu | 7-6,6-3 |
| ITF W60 Amstelveen | 2021/07/05 10:25 | Stewart, Katerina v Alexandra Osborne | 4-6,1-6 |
| ITF W60 Charleston | 2021/06/23 13:30 | Maria Mateas v Stewart, Katerina | 6-4,0-6,7-6 |
| ITF W25 Pelham | 2021/05/19 16:00 | Stewart, Katerina v Contreras Gomez, Fernanda | 1-6,2-6 |
| ITF - W100 Bonita Springs | 2021/05/10 18:55 | Stewart, Katerina v Ulrikke Eikeri | 5-7,5-7 |
| ITF W25 Naples | 2021/05/07 13:30 | Irina Fetecau v Stewart, Katerina | 6-2,1-6,6-1 |
| ITF W25 Naples | 2021/05/06 13:00 | Stewart, Katerina v Kayla Day | 3-6,6-2,6-2 |
| ITF W25 Naples | 2021/05/05 20:55 | Stewart, Katerina v Anna Siskova | 1-6,6-2,6-3 |
| ITF W60 Charlottesville | 2021/04/26 18:55 | Kayla Day v Stewart, Katerina | 6-3,6-3 |