Stadium: Grandstand Round: 26 Ground: Hardcourt outdoor
| ATP Montpellier MD | 2018/02/08 13:45 | Koolhof/Sitak v Arends/Sancic | 6-3,4-6,5-10 |
| ATP Montpellier MD | 2018/02/07 19:25 | Dodig/Ram v Koolhof/Sitak | 6-2,5-7,0-10 |
| 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 |