Stadium: Court 3 Round: 26 Ground: Clay
| Challenger Eckental | 2018/10/28 10:00 | Igor Sijsling v Simon, Tobias | 3-6,7-6,6-2 |
| Vogau, Singles Qualifying M-ITF-AUT-04A | 2020/08/19 08:00 | Francisco Cerundolo v Simon, Tobias | 3-6,6-7 |
| German Premier League | 2020/07/29 14:55 | Kohlschreiber, Philipp v Simon, Tobias | 6-4,6-2 |
| German Premier League | 2020/07/28 11:50 | Simon, Tobias v Fomba, Luc | 7-6,6-2 |
| German Premier League | 2020/07/27 13:00 | Simon, Tobias v Alexey Vatutin | 6-7,6-3,2-6 |
| DTB German Pro Series | 2020/06/11 09:30 | Max Hans Rehberg v Simon, Tobias | 3-6,7-6,6-3 |
| DTB German Pro Series | 2020/06/10 14:35 | Yannick Hanfmann v Simon, Tobias | 6-3,6-2 |
| DTB German Pro Series | 2020/06/09 11:00 | Bachinger, Matthias v Simon, Tobias | 4-6,6-7 |
| Challenger Potchefstroom | 2020/03/11 09:30 | Moundir, Adam v Simon, Tobias | 5-7,3-6 |
| Vogau, Singles Qualifying M-ITF-AUT-04A | 2020/08/19 13:15 | Dubrivnyy, Artem v Igor Sijsling | 7-6,3-6,4-6 |
| Vogau, Singles Qualifying M-ITF-AUT-04A | 2020/08/18 07:00 | Igor Sijsling v Hampel, Lenny | 6-2,6-1 |
| Vogau, Singles Qualifying M-ITF-AUT-04A | 2020/08/17 11:30 | Igor Sijsling v Spec, Matic | 6-4,6-4 |
| Vogau, Singles Qualifying M-ITF-AUT-04A | 2020/08/16 12:00 | Igor Sijsling v Aichhorn, Jakob | 6-1,6-1 |
| Exo Tennis Germany Series | 2020/07/18 13:15 | Igor Sijsling v Daniel Vishnick | 6-0,6-2 |
| Exo Tennis Germany Series | 2020/07/17 17:00 | Igor Sijsling v Florian Broska | 6-4,5-7,6-3 |
| ITF - M25 Sunderland | 2020/03/01 12:40 | Jack Draper v Igor Sijsling | 6-2,6-0 |
| ITF - M25 Sunderland | 2020/02/29 10:25 | Igor Sijsling v Jesper De Jong | 6-2,1-6,6-2 |