Stadium: Court 2 Round: 25 Ground: Hardcourt outdoor
| Challenger Zadar | 2021/03/23 10:45 | Gianluca Mager v Igor Sijsling | 6-4,4-6,6-4 |
| Challenger St. Petersburg | 2021/03/09 12:30 | Kacper Zuk v Igor Sijsling | 6-4,6-3 |
| Challenger St. Petersburg | 2021/03/02 09:45 | Igor Sijsling v Artem Dubrivnyy | 6-3,4-6,3-6 |
| Challenger Cherbourg | 2021/02/08 18:45 | Igor Sijsling v Evan Furness | 2-6,4-6 |
| ITF M15 Bressuire | 2021/01/22 10:00 | Igor Sijsling v Gijs Brouwer | 5-7,3-6 |
| ITF M15 Bressuire | 2021/01/21 09:30 | Igor Sijsling v Lilian Marmousez | 6-1,7-6 |
| ITF M15 Bressuire | 2021/01/19 11:15 | Igor Sijsling v Axel Garcian | 6-2,6-2 |
| Challenger Maia | 2020/11/28 15:00 | Igor Sijsling v Duje Ajdukovic | 2-6,1-6 |
| Challenger Zadar | 2021/03/23 13:30 | Teymuraz Gabashvili v Ivan Nedelko | 2-6,6-2,3-6 |
| ATP Dubai | 2021/03/13 09:20 | Lloyd Harris v Teymuraz Gabashvili | 6-1,6-2 |
| Challenger St. Petersburg | 2021/03/09 10:15 | Altug Celikbilek v Teymuraz Gabashvili | 6-2,6-2 |
| Challenger St. Petersburg | 2021/03/02 11:25 | Teymuraz Gabashvili v Pavel Kotov | 4-6,2-6 |
| Challenger Potchefstroom | 2021/02/21 08:00 | Teymuraz Gabashvili v Jenson Brooksby | 6-2,3-6,0-6 |
| Challenger Potchefstroom | 2021/02/20 11:10 | Teymuraz Gabashvili v Liam Broady | 1-6,6-4,6-4 |
| Challenger Potchefstroom | 2021/02/19 08:00 | Akira Santillan v Teymuraz Gabashvili | 6-7,6-4,3-6 |
| Challenger Potchefstroom | 2021/02/17 10:30 | Teymuraz Gabashvili v Ulises Blanch | 6-4,1-6,6-3 |