Stadium: Court 4 Round: 46 Ground: Grass
| Challenger Vancouver Qual | 2017/08/12 19:05 | Austin Krajicek v Frederik Nielsen | 2-6,3-6 |
| Challenger Busan Qual | 2017/05/14 03:10 | Austin Krajicek v Frederik Nielsen | 6-3,6-2 |
| Challenger Nottingham Qual | 2018/06/09 16:45 | Frederik Nielsen v Daniil Zarichanskiy | 6-3,6-1 |
| Challenger Loughborough | 2018/05/22 12:30 | Frederik Nielsen v David Guez | 2-6,4-6 |
| Challenger Loughborough Qual | 2018/05/21 09:30 | Johannes Haerteis v Frederik Nielsen | 6-7,1-6 |
| Challenger Loughborough Qual | 2018/05/20 09:30 | Simon Carr v Frederik Nielsen | 3-6,4-6 |
| Challenger Loughborough Qual | 2018/05/19 09:00 | Remi Boutillier v Frederik Nielsen | 7-6,6-7,1-6 |
| Challenger Busan Qual | 2018/05/14 03:30 | Yosuke Watanuki v Frederik Nielsen | 1-6,6-4,6-0 |
| Challenger Busan Qual | 2018/05/13 04:10 | Frederik Nielsen v Wishaya Trongcharoenchaikul | 6-7,6-4,6-0 |
| Challenger Seoul Qual | 2018/04/28 04:30 | Yong-Kyu Lim v Frederik Nielsen | 6-4,6-1 |
| Challenger Nottingham Qual | 2018/06/09 14:35 | Tiran Sanghera v Austin Krajicek | 3-6,2-6 |
| Challenger Puerto Vallarta | 2018/04/30 20:30 | Austin Krajicek v Edan Leshem | 3-6,4-6 |
| Challenger Mexico City | 2018/04/10 21:20 | Juan Ignacio Londero v Austin Krajicek | 7-5,6-1 |
| Challenger Mexico City Qual | 2018/04/09 19:00 | Austin Krajicek v Gonzalo Escobar | 7-5,2-6,7-6 |
| Challenger Mexico City Qual | 2018/04/08 18:55 | Austin Krajicek v Alexios Halebian | 6-4,6-0 |
| Challenger Mexico City Qual | 2018/04/07 19:30 | Austin Krajicek v Shalva Dzhanashia | 6-3,6-3 |
| Challenger San Luis Potosi | 2018/03/29 22:15 | Austin Krajicek v Jose Hernandez-Fernandez | 0-6,2-6 |
| Challenger San Luis Potosi | 2018/03/29 01:10 | Paolo Lorenzi v Austin Krajicek | 7-6,1-6,3-6 |