Stadium: Grandstand Round: 26 Ground: Hardcourt outdoor
| ATP Montpellier MD | 2018/02/08 13:45 | Koolhof W / Sitak A v Arends S / Sancic A | 6-3,4-6,5-10 |
| ATP Montpellier MD | 2018/02/07 19:25 | Dodig I / Ram R v Koolhof W / Sitak A | 6-2,5-7,0-10 |
| Newport Beach, USA, Doubles | 2018/01/24 23:50 | Koolhof W / Sitak A v 후에이 T / 쿠들라 D | 2-6,1-6 |
| Australian Open MD | 2018/01/19 01:30 | Koolhof W / Sitak A v 마라치 O / 파비치 M | 7-6,4-6,4-6 |
| Australian Open MD | 2018/01/17 01:40 | Gojowczyk P / Mayer F v Koolhof W / Sitak A | 2-6,1-6 |
| Auckland, New Zealand, Doubles | 2018/01/09 08:30 | Koolhof W / Sitak A v 칼라센 R / 베너스 M | 1-6,7-6,7-10 |
| Brisbane, Australia, Doubles | 2018/01/06 01:30 | Koolhof W / Sitak A v 메이어 L / 제볼로즈 H | 6-4,1-6,6-10 |
| Brisbane, Australia, Doubles | 2018/01/03 03:10 | Koolhof W / Sitak A v Johnson/Muller | 7-6,7-5 |