Stadium: Centre Court Round: 26 Ground: Hardcourt indoor
| Challenger Glasgow | 2018/05/01 09:30 | Bernabe Zapata Miralles v Igor Sijsling | 1-6,3-6 |
| ITF Portugal F8 | 2018/04/17 10:00 | Germain Gigounon v Igor Sijsling | 6-4,6-2 |
| ITF Portugal F7 | 2018/04/12 17:40 | Germain Gigounon v Igor Sijsling | 6-4,6-3 |
| ITF Portugal F7 | 2018/04/12 11:00 | Igor Sijsling v Joao Monteiro | 6-2,6-1 |
| Challenger St Brieuc Qual | 2018/03/26 11:05 | Constant Lestienne v Igor Sijsling | 6-2,5-7,7-6 |
| Challenger St Brieuc Qual | 2018/03/25 11:55 | Igor Sijsling v Zizou Bergs | 7-5,7-5 |
| Challenger St Brieuc Qual | 2018/03/24 17:05 | Igor Sijsling v Pierre Faivre | 6-4,6-2 |
| ITF France F5 | 2018/03/18 14:00 | Antoine Hoang v Igor Sijsling | 3-6,6-1,6-4 |
| Challenger Glasgow | 2018/05/01 10:30 | Mario Vilella Martinez v Roberto Ortega-Olmedo | 6-7,4-6 |
| Challenger Anning | 2018/04/24 05:05 | Roberto Ortega-Olmedo v Jordan Thompson | 3-6,3-6 |
| Challenger Nanchang | 2018/04/20 04:20 | Roberto Ortega-Olmedo v Jordan Thompson | 6-4,2-6,2-6 |
| Challenger Nanchang | 2018/04/18 06:10 | Roberto Ortega-Olmedo v Mukund Sasikumar | 6-4,6-2 |
| Challenger Nanchang | 2018/04/17 04:50 | Go Soeda v Roberto Ortega-Olmedo | 4-6,6-7 |
| Challenger Taipei | 2018/04/10 03:00 | Yuki Bhambri v Roberto Ortega-Olmedo | 6-7,6-3,6-3 |
| ITF Portugal F6 | 2018/03/29 09:30 | Roberto Ortega-Olmedo v Lloyd Harris | 6-4,6-7,4-6 |
| ITF Portugal F6 | 2018/03/28 09:30 | Roberto Ortega-Olmedo v Romain Barbosa | 5-7,6-4,7-6 |