Stadium: Court 1 Round: 25 Ground: Clay
| ITF M25 - Bakio | 2021/06/29 13:00 | Pablo Llamas Ruiz v Tobias Simon | 7-5,6-2 |
| ITF M25 - Klosters | 2021/06/24 08:35 | Dominic Stephan Stricker v Tobias Simon | 7-6,6-7,6-3 |
| ITF M25 - Klosters | 2021/06/23 12:00 | Tomas Papik v Tobias Simon | 3-6,4-6 |
| Challenger - Forli | 2021/06/14 09:30 | Thiago Agustin Tirante v Tobias Simon | 7-6,6-3 |
| Challenger - Forli | 2021/06/13 14:15 | Matteo Arnaldi v Tobias Simon | 6-7,2-6 |
| ITF M15 - Gaiba | 2021/06/11 10:00 | Benjamin Lock v Tobias Simon | 6-2,6-3 |
| ITF M15 - Gaiba | 2021/06/10 14:45 | Federico Bertuccioli v Tobias Simon | 4-6,3-6 |
| ITF M15 - Gaiba | 2021/06/09 15:55 | Andrea Picchione v Tobias Simon | 5-7,7-6,5-7 |
| ITF M15 - Frederiksberg | 2021/08/06 09:00 | Jonathan Mridha v Christian Sigsgaard | 6-4,6-4 |
| ITF M15 - Frederiksberg | 2021/08/05 10:25 | Christian Sigsgaard v Daniel De Jonge | 6-4,7-6 |
| ITF M15 - Frederiksberg | 2021/08/03 09:45 | Christian Sigsgaard v Giorgio Ricca | 6-3,6-3 |
| ITF M15 - Vejle | 2021/07/29 14:35 | Henrik Heise Korsgaard v Christian Sigsgaard | 7-5,6-2 |
| ITF M15 - Vejle | 2021/07/28 12:50 | Christian Sigsgaard v Ryan Nijboer | 6-3,6-2 |
| ITF M15 - Heraklion | 2021/05/31 06:30 | Christian Sigsgaard v Sean Hodkin | 2-6,7-5,6-10 |
| ITF M15 - Heraklion | 2021/05/30 09:00 | Matic Dimic v Christian Sigsgaard | 3-6,2-6 |
| ITF M15 - Tbilisi | 2021/05/22 06:00 | Christian Sigsgaard v Alexander Shevchenko | 6-7,6-7 |