Stadium: Court 1 Round: 26 Ground: Clay
| ATP Delray Beach MD | 2018/02/21 16:00 | Koolhof W / Sitak A v Lipsky S / Sharan D | 6-7,2-6 |
| ATP New York MD | 2018/02/18 18:00 | Koolhof W / Sitak A v Mirnyi M / Oswald P | 4-6,6-4,6-10 |
| ATP New York MD | 2018/02/18 03:05 | Koolhof W / Sitak A v 알보트 R / 바실라시빌리 N | 6-4,6-3 |
| ATP New York MD | 2018/02/16 22:30 | 카르디 J / 마르틴 F v Koolhof W / Sitak A | 4-6,6-3,6-10 |
| ATP New York MD | 2018/02/14 18:00 | Koolhof W / Sitak A v Nestor D / Skupski N | 6-3,6-1 |
| 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 |