Stadium: Pista 2 Round: 25 Ground: Clay
| ATP Belgrade | 2021/05/23 10:30 | Pedja Krstin v Soonwoo Kwon | 6-2,3-6,6-1 |
| ITF M15 Prijedor | 2021/05/11 15:05 | Pedja Krstin v Mateja Janicijevic | 6-1,6-0 |
| Challenger Rome Qual | 2021/04/25 09:15 | Matteo Gigante v Pedja Krstin | 4-6,7-5,6-4 |
| Challenger Belgrade | 2021/04/12 16:00 | Damir Dzumhur v Pedja Krstin | 4-6,6-2,6-3 |
| Challenger St. Petersburg | 2021/03/10 08:30 | Zizou Bergs v Pedja Krstin | 6-2,6-1 |
| Challenger St. Petersburg | 2021/03/03 07:00 | Matthew Ebden v Pedja Krstin | 6-1,6-4 |
| Challenger Potchefstroom | 2021/02/16 10:55 | Lucas Miedler v Pedja Krstin | 6-2,6-0 |
| Challenger Potchefstroom | 2021/02/08 12:55 | Roberto Cid Subervi v Pedja Krstin | 3-6,5-7 |
| Challenger Heilbronn | 2021/05/09 10:00 | Joao Menezes v Nicola Kuhn | 6-1,6-4 |
| Challenger Biella | 2021/05/03 10:15 | Nicola Kuhn v Felipe Meligeni Rodrigues Alves | 2-6,4-6 |
| Challenger Biella | 2021/05/02 12:40 | Quentin Halys v Nicola Kuhn | 6-7,2-6 |
| Challenger Oeiras | 2021/04/05 14:00 | Nicola Kuhn v Manuel Guinard | 1-6,4-6 |
| Challenger Oeiras | 2021/03/31 10:00 | Raul Brancaccio v Nicola Kuhn | 6-1,6-2 |
| Challenger Oeiras | 2021/03/29 12:00 | Nicola Kuhn v Teymuraz Gabashvili | 6-3,6-3 |
| Challenger Lille | 2021/03/25 16:20 | Arthur Rinderknech v Nicola Kuhn | 6-3,6-1 |
| Challenger Lille | 2021/03/23 10:45 | Matteo Martineau v Nicola Kuhn | 3-6,2-6 |