Stadium: Estadio Millennium Round: 29 Ground: Clay
| Challenger Newport Beach MD | 2018/01/24 23:50 | Koolhof/Sitak v Huey/Kudla | 2-6,1-6 |
| Australian Open MD | 2018/01/19 01:30 | Koolhof/Sitak v Marach/Pavic | 7-6,4-6,4-6 |
| Australian Open MD | 2018/01/17 01:40 | Gojowczyk/Mayer v Koolhof/Sitak | 2-6,1-6 |
| ATP Auckland MD | 2018/01/09 08:30 | Koolhof/Sitak v Klaasen/Venus | 1-6,7-6,7-10 |
| ATP Brisbane MD | 2018/01/06 01:30 | Koolhof/Sitak v Mayer/Zeballos | 6-4,1-6,6-10 |
| ATP Brisbane MD | 2018/01/03 03:10 | Koolhof/Sitak v Johnson/Muller | 7-6,7-5 |
| ATP Brisbane MD | 2018/01/01 01:00 | Koolhof/Sitak v Huey/Martin | 6-3,6-2 |
| Challenger Mouilleron le Captif MD | 2017/11/11 12:00 | Koolhof/Sitak v Bednarek/Pel | 6-4,6-7,10-12 |