| Latvia Int. XD | 2021/08/28 07:00 | Mueller/Stern v Azman/Low | L | 0-2 |
| Latvia Int. XD | 2021/08/27 10:00 | Mueller/Stern v Xu/Christensen | W | 2-0 |
| Denmark Masters XD | 2021/08/06 07:00 | Ivancic/Polanc v Mueller/Stern | L | 2-1 |
| Spain Int XD | 2021/06/18 13:00 | Mueller/Stern v Birker P / Hochmeir K | L | 1-2 |
| Spain Int XD | 2021/06/18 07:45 | Mueller/Stern v De Wit/Van Wijlick | W | 2-0 |
| Spain Int XD | 2021/06/17 11:40 | Mueller/Stern v Magee J / Boyle S | W | 2-1 |
| Open de Pologne - Doubles Mixtes | 2021/03/28 08:00 | Choong/Toh v Mueller/Stern | L | 2-0 |
| Open de Pologne - Doubles Mixtes | 2021/03/27 16:00 | Mueller/Stern v Kargaev R / Vorobeva V | W | 2-1 |
| Hellas Int. XD Qual | 2021/09/02 16:00 | Tores/Vercelot v Zekan/Cvitkusic | W | 2-0 |
| Lithuanian Int. - Doubles Mixtes | 2021/06/12 06:00 | Vestergaard/Lober v Tores/Vercelot | L | 2-1 |