Stadium: Court 4 Round: 46 Ground: Grass
| Challenger Vancouver Qual | 2017/08/12 19:05 | Krajicek, Austin v Nielsen, Frederik | 2-6,3-6 |
| Challenger Busan Qual | 2017/05/14 03:10 | Krajicek, Austin v Nielsen, Frederik | 6-3,6-2 |
| Challenger Nottingham Qual | 2018/06/09 16:45 | Nielsen, Frederik v 자리찬스키, 다닐 | 6-3,6-1 |
| Challenger Loughborough | 2018/05/22 12:30 | Nielsen, Frederik v Guez, David | 2-6,4-6 |
| Challenger Loughborough Qual | 2018/05/21 09:30 | 헤르테스, 조하네스 v Nielsen, Frederik | 6-7,1-6 |
| Challenger Loughborough Qual | 2018/05/20 09:30 | 칼, 시몬 v Nielsen, Frederik | 3-6,4-6 |
| Challenger Loughborough Qual | 2018/05/19 09:00 | Boutillier, Remi v Nielsen, Frederik | 7-6,6-7,1-6 |
| Challenger Busan Qual | 2018/05/14 03:30 | 와타누키, 요스케 v Nielsen, Frederik | 1-6,6-4,6-0 |
| Challenger Busan Qual | 2018/05/13 04:10 | Nielsen, Frederik v 트롱차로엔차이쿨, 위사야 | 6-7,6-4,6-0 |
| Challenger Seoul Qual | 2018/04/28 04:30 | 임, 영규 v Nielsen, Frederik | 6-4,6-1 |
| Challenger Nottingham Qual | 2018/06/09 14:35 | Sanghera, Tiran v Krajicek, Austin | 3-6,2-6 |
| Puerto Vallarta, Mexico | 2018/04/30 20:30 | Krajicek, Austin v 레셈, 에단 | 3-6,4-6 |
| Challenger Mexico City | 2018/04/10 21:20 | 론데로, 주안 이그나시오 v Krajicek, Austin | 7-5,6-1 |
| Challenger Mexico City Qual | 2018/04/09 19:00 | Krajicek, Austin v 에스코발, 곤잘로 | 7-5,2-6,7-6 |
| Challenger Mexico City Qual | 2018/04/08 18:55 | Krajicek, Austin v 할레비안, 알렉시오스 | 6-4,6-0 |
| Challenger Mexico City Qual | 2018/04/07 19:30 | Krajicek, Austin v 드자나시아, 살바 | 6-3,6-3 |
| Challenger San Luis Potosi | 2018/03/29 22:15 | Krajicek, Austin v 헤르난데즈-페르난데즈, 조세 | 0-6,2-6 |
| Challenger San Luis Potosi | 2018/03/29 01:10 | 로렌지, 파올로 v Krajicek, Austin | 7-6,1-6,3-6 |