Stadium: Court 3 Round: 25 Ground: Hardcourt indoor
| Challenger Biel | 2021/09/20 09:00 | Hiroki Moriya v Anton Matusevich | 6-4,5-7,6-4 |
| Challenger Biel | 2021/09/19 08:00 | Anton Matusevich v Alessandro Bega | 6-2,6-1 |
| ITF M25 Sintra | 2021/09/09 11:25 | Anton Matusevich v Paul Jubb | 6-7,6-7 |
| ITF M25 Sintra | 2021/09/08 09:00 | Anton Matusevich v Daniel Little | 6-4,6-4 |
| ITF M25 Idanha-A-Nova | 2021/07/23 09:00 | Anton Matusevich v Gilbert S K Junior | 3-6,3-6 |
| ITF M25 Idanha-A-Nova | 2021/07/22 11:55 | Anton Matusevich v Luis Faria | 6-3,2-6,7-6 |
| ITF M25 Idanha-A-Nova | 2021/07/20 10:45 | Anton Matusevich v Naoki Tajima | 6-3,7-5 |
| ITF M25 Idanha-A-Nova | 2021/07/17 08:30 | Nicolas Moreno De Alboran v Anton Matusevich | 7-6,6-4 |
| ITF M15 Doha | 2021/10/13 14:15 | Oscar Moraing v Christian Sigsgaard | 6-4,6-2 |
| ITF M15 Doha | 2021/10/08 12:30 | Christian Sigsgaard v Oscar Moraing | 6-3,1-6,2-6 |
| ITF M15 Doha | 2021/10/07 14:50 | Christian Sigsgaard v Boris Butulija | 6-1,6-3 |
| ITF M15 Doha | 2021/10/06 15:30 | Saketh Myneni v Christian Sigsgaard | 4-6,4-6 |
| ITF M25 Falun | 2021/09/29 14:50 | Antoine Escoffier v Christian Sigsgaard | 7-5,6-7,6-4 |
| ITF M25 Falun | 2021/09/28 12:45 | Leo Borg v Christian Sigsgaard | 3-6,4-6 |
| ITF M25 Falun | 2021/09/26 11:00 | Christian Sigsgaard v Jonathan Backman | 6-1,6-4 |
| Davis Cup | 2021/09/17 14:00 | Christian Sigsgaard v Wishaya Trongcharoenchaikul | 6-3,6-2 |