stadio: Pista 2 Round: 26 Ground: Hardcourt outdoor
| Challenger Irving DM | 2018/03/16 23:10 | Petzschner/Peya v Koolhof/Sitak | 6-4,7-5 |
| Challenger Irving DM | 2018/03/15 22:25 | Koolhof/Sitak v Krajicek/Lacko | 6-1,6-4 |
| Challenger Irving DM | 2018/03/14 19:00 | Inglot/Skupski v Koolhof/Sitak | 6-3,1-6,6-10 |
| ATP San Paolo DM | 2018/03/04 17:20 | Koolhof/Sitak v Delbonis/Gonzalez | 4-6,2-6 |
| ATP San Paolo DM | 2018/03/03 20:00 | Berlocq/Kicker v Koolhof/Sitak | 3-6,3-6 |
| ATP San Paolo DM | 2018/02/28 20:45 | Koolhof/Sitak v C Baena/Garcia-Lopez | 7-5,6-4 |
| ATP San Paolo DM | 2018/02/27 23:10 | Koolhof/Sitak v Arends/Begemann | 6-4,7-6 |
| ATP Delray Beach DM | 2018/02/21 16:00 | Koolhof/Sitak v Lipsky/Sharan | 6-7,2-6 |