Stadium: Pista 2 Round: 27 Ground: Hardcourt outdoor
| Challenger Alicante MD | 2018/04/02 12:35 | Koolhof W / Sitak A v Cervantes I / Marrero D | 6-4,6-1 |
| Irving, USA, Doubles | 2018/03/16 23:10 | Petzschner P / Peya A v Koolhof W / Sitak A | 6-4,7-5 |
| Irving, USA, Doubles | 2018/03/15 22:25 | Koolhof W / Sitak A v Krajicek/Lacko | 6-1,6-4 |
| Irving, USA, Doubles | 2018/03/14 19:00 | Inglot/Skupski v Koolhof W / Sitak A | 6-3,1-6,6-10 |
| Sao Paulo, Brazil, Doubles | 2018/03/04 17:20 | Koolhof W / Sitak A v Delbonis F / Gonzalez M | 4-6,2-6 |
| Sao Paulo, Brazil, Doubles | 2018/03/03 20:00 | Berlocq C / Kicker N v Koolhof W / Sitak A | 3-6,3-6 |
| Sao Paulo, Brazil, Doubles | 2018/02/28 20:45 | Koolhof W / Sitak A v 칼발레스 바에나 로 / 가르시아-로페즈 구 | 7-5,6-4 |
| Sao Paulo, Brazil, Doubles | 2018/02/27 23:10 | Koolhof W / Sitak A v Arends/Begemann | 6-4,7-6 |
| Challenger Alicante MD | 2018/04/03 14:30 | 아르나볼디 안 / 지아네시 알 v Junaid R / Oliveira G | 7-5,7-5 |
| Challenger Caltanissetta MD | 2016/06/09 20:15 | 아르나볼디 안 / 지아네시 알 v Cerretani J / Schnur M J | 5-7,5-7 |