| Coupe Davis | 02/03 12:00 | 168 | Koolhof/Jean-Julien Rojer v Huesler/Riedi | 6-7,6-7 | |
| Coupe Davis | 02/03 12:00 | 168 | Koolhof/Jean-Julien Rojer v Kym/Ritschard | Cancelled | |
| Coupe Davis | 11/23 13:55 | 27 | Bolelli S / Sonego L v Koolhof/Jean-Julien Rojer | Cancelled | |
| ATP Paris MD | 11/01 11:50 | 25 | Martin F / Mies A v Koolhof/Jean-Julien Rojer | 6-3,7-5 | |
| ATP Vienna MD | 10/26 17:55 | 26 | Cabal / Farah v Koolhof/Jean-Julien Rojer | 4-6,6-3,10-8 | |
| ATP Antwerp MD | 10/24 12:00 | 29 | Koolhof/Jean-Julien Rojer v Mahut/Martin | 0-6,1-6 | |
| ATP Antwerp MD | 10/23 17:10 | 28 | Harris/Malisse v Koolhof/Jean-Julien Rojer | 4-6,2-6 | |
| ATP Antwerp MD | 10/21 08:00 | 27 | Koolhof/Jean-Julien Rojer v Musetti/Paire | Walkover | |
| ATP Antwerp MD | 10/20 12:20 | 26 | Koolhof/Jean-Julien Rojer v Jebavy R / Vasilevski A | 6-4,6-2 | |
| ATP Indian Wells - Doubles Hommes | 10/12 21:35 | 26 | Koolhof/Jean-Julien Rojer v Peers/Polasek | 4-6,6-7 | |
| ATP Indian Wells - Doubles Hommes | 10/10 18:00 | 25 | Koolhof/Jean-Julien Rojer v Krajicek/Mies | 1-6,7-6,10-5 | |
| US Open MD | 09/06 20:20 | 26 | Peers/Polasek v Koolhof/Jean-Julien Rojer | 4-6,6-3,6-4 | |
| US Open MD | 09/04 15:00 | 25 | Galloway R / Lawson A v Koolhof/Jean-Julien Rojer | 3-6,6-7 | |
| US Open MD | 09/03 17:00 | 24 | Karatsev/Nedovyesov v Koolhof/Jean-Julien Rojer | 6-7,1-6 | |
| Olympics 2020 - MD | 07/26 06:15 | 26 | Koolhof/Jean-Julien Rojer v Daniell M / Venus M | Walkover | |
| Olympics 2020 - MD | 07/24 02:00 | 25 | Koolhof/Jean-Julien Rojer v Gille/Vliegen | 6-3,7-6 | |
| Wimbledon MD | 07/01 17:00 | 24 | Koolhof/Jean-Julien Rojer v Glasspool/Heliovaara | 7-5,3-6,4-6 | |
| ATP Halle MD | 06/17 10:35 | 26 | Koolhof/Jean-Julien Rojer v Auger-Aliassime F / Hurkacz H | 6-7,3-6 | |
| French Open MD | 06/05 12:25 | 26 | Koolhof/Jean-Julien Rojer v Bublik A / Golubev A | 6-7,6-3,4-6 | |
| French Open MD | 06/04 11:25 | 25 | Koolhof/Jean-Julien Rojer v Koepfer/Ruusuvuori | 6-4,7-6 | |
| French Open MD | 06/01 12:45 | 24 | Koolhof/Jean-Julien Rojer v Krajinovic F / Lajovic D | 6-4,4-6,6-2 | |
| ATP - Rome - Doubles Hommes | 05/14 08:00 | 27 | Arevalo/Middelkoop v Koolhof/Jean-Julien Rojer | 2-6,7-6,10-5 | |
| ATP - Rome - Doubles Hommes | 05/13 08:00 | 26 | Behar A / Escobar G v Koolhof/Jean-Julien Rojer | 6-4,3-6,8-10 | |
| ATP - Rome - Doubles Hommes | 05/11 11:40 | 25 | Cecchinato/Travaglia v Koolhof/Jean-Julien Rojer | 6-4,1-6,7-10 | |
| Coupe Davis | 03/07 06:00 | 45 | Golubev A / Nedovyesov A v Koolhof/Jean-Julien Rojer | Cancelled | |
| Coupe Davis | 11/20 16:05 | 3 | Murray J / Skupski N v Koolhof/Jean-Julien Rojer | 6-4,7-6 | |
| Coupe Davis | 11/19 14:15 | 3 | Golubev A / Nedovyesov A v Koolhof/Jean-Julien Rojer | Cancelled |