Stadium: Center Court Round: 27 Ground: Clay
| Challenger Manama | 2021/11/22 14:20 | Ryan Peniston v Christopher O'Connell | 6-7,6-3,7-6 |
| Challenger Bergamo | 2021/11/03 15:05 | Christopher O'Connell v Zdenek Kolar | 7-5,6-7,5-7 |
| Challenger Bergamo | 2021/11/02 18:05 | Christopher O'Connell v Yannick Maden | 6-3,7-6 |
| Challenger Saint-Tropez | 2021/09/04 14:15 | Thanasi Kokkinakis v Christopher O'Connell | 1-6,6-7 |
| Challenger Saint-Tropez | 2021/09/03 11:25 | Alexandre Muller v Christopher O'Connell | 6-7,4-6 |
| Challenger Saint-Tropez | 2021/09/01 11:20 | Dragos Nicolae Madaras v Christopher O'Connell | 1-6,4-6 |
| Challenger Saint-Tropez | 2021/08/31 12:05 | Jurgen Briand v Christopher O'Connell | 2-6,4-6 |
| US Open | 2021/08/26 19:25 | Christopher O'Connell v Mats Moraing | 6-7,1-6 |
| Challenger Bratislava | 2021/11/11 10:00 | Kacper Zuk v Jiri Lehecka | 6-2,3-6,2-6 |
| Challenger Bratislava | 2021/11/10 09:00 | Shintaro Mochizuki v Kacper Zuk | 6-7,3-6 |
| Challenger Eckental | 2021/11/02 17:05 | Maximilian Marterer v Kacper Zuk | 6-3,6-4 |
| Challenger Ismaning | 2021/10/29 10:30 | Maxime Cressy v Kacper Zuk | 6-7,6-4,7-6 |
| Challenger Ismaning | 2021/10/27 13:55 | Kacper Zuk v Andreas Seppi | 4-6,6-4,7-6 |
| Challenger Ismaning | 2021/10/25 17:15 | Vitaliy Sachko v Kacper Zuk | 2-6,4-6 |
| Challenger Alicante | 2021/10/13 09:30 | Kacper Zuk v Lucas Miedler | 5-7,3-6 |
| Challenger Alicante | 2021/10/11 14:15 | Kacper Zuk v Teymuraz Gabashvili | 5-7,7-6,6-3 |