Stadium: Court 8 Round: 26 Ground: Clay
| ITF M25 Praha | 2021/05/11 14:15 | Thai-Son Kwiatkowski v Filip Duda | 6-3,6-1 |
| Challenger Tallahassee | 2021/04/23 17:35 | Bjorn Fratangelo v Thai-Son Kwiatkowski | 7-5,6-4 |
| Challenger Tallahassee | 2021/04/22 19:30 | Thai-Son Kwiatkowski v Jason Jung | 6-3,6-2 |
| Challenger Tallahassee | 2021/04/20 16:45 | Thai-Son Kwiatkowski v Mitchell Krueger | 3-6,7-6,6-3 |
| Challenger Orlando | 2021/04/13 16:05 | Thai-Son Kwiatkowski v Altug Celikbilek | 2-6,3-6 |
| ATP Miami | 2021/03/22 17:10 | Thai-Son Kwiatkowski v Alejandro Tabilo | 3-6,4-6 |
| Challenger Cleveland | 2021/03/15 23:05 | Thai-Son Kwiatkowski v Bjorn Fratangelo | 4-6,2-6 |
| ATP Singapore | 2021/02/24 04:00 | Soonwoo Kwon v Thai-Son Kwiatkowski | 4-6,6-3,6-4 |
| ITF M25 Praha | 2021/05/12 09:30 | Markus Eriksson v Patrik Rikl | 4-6,5-7 |
| ITF M25 Praha | 2021/05/11 08:00 | Pavel Nejedly v Patrik Rikl | 2-6,2-6 |
| ITF M25 Praha | 2021/05/10 10:30 | Antonin Bolardt v Patrik Rikl | 1-6,4-6 |
| ITF M25 Praha | 2021/05/09 12:30 | Peter Samosi v Patrik Rikl | 4-6,0-6 |
| Challenger Praha | 2021/05/02 12:00 | Kacper Zuk v Patrik Rikl | 4-6,7-6,6-3 |
| Challenger Ostrava | 2021/04/27 09:10 | Patrik Rikl v Sergiy Stakhovsky | 4-6,2-6 |
| ITF M15 St Petersburg | 2021/04/15 12:00 | Patrik Rikl v Yanki Erel | 3-6,5-7 |
| ITF M15 St Petersburg | 2021/04/13 11:30 | Patrik Rikl v Aristarkh Safonov | 6-4,6-2 |