| Open d'Australie | 01/19 04:50 | 25 | Seppi, Andreas v Karlovic, Ivo | 6-3,7-6,6-7,6-7,9-7 | |
| Open d'Australie | 01/17 02:20 | 24 | Karlovic, Ivo v Sugita, Yuichi | 7-6,6-7,7-5,4-6,12-10 | |
| Open d'Australie | 01/15 05:15 | 23 | Karlovic, Ivo v Laslo Djere | 7-6,6-3,7-6 | |
| Antwerp, Belgium | 10/19 10:00 | 26 | [51] Karlovic, Ivo v Stefanos Tsitsipas [122] | Retired | |
| Antwerp, Belgium | 10/16 12:55 | 25 | [51] Karlovic, Ivo v Pella, Guido [64] | 3-6,7-5,7-6 | |
| Shanghai, Chine | 10/09 05:00 | 24 | [34] Lopez, Feliciano v Karlovic, Ivo [49] | 7-6,7-6 | |
| ATP Tokyo | 10/02 10:55 | 25 | [49] Karlovic, Ivo v Ebden, Matthew [139] | 4-6,3-6 | |
| US Open, New York, USA | 08/29 15:00 | 23 | [135] Fratangelo, Bjorn v Karlovic, Ivo [38] | 7-6,6-4,3-6,7-6 | |
| Cincinnati, USA | 08/17 22:55 | 26 | [23] Kyrgios, Nick v Karlovic, Ivo [44] | 4-6,7-6,6-3 | |
| Cincinnati, USA | 08/15 23:00 | 25 | [44] Karlovic, Ivo v Tsonga, Jo-Wilfried [12] | 6-4,7-6 | |
| Cincinnati, USA | 08/14 15:00 | 24 | [44] Karlovic, Ivo v Jiri Vesely [52] | 6-3,3-6,7-5 | |
| ATP - Los Cabos | 08/02 00:00 | 25 | [31] Karlovic, Ivo v Quentin Halys [126] | 6-7,6-7 | |
| Newport, USA | 07/20 19:35 | 27 | [131] Gojowczyk, Peter v Karlovic, Ivo [25] | 7-6,6-7,7-6 | |
| Newport, USA | 07/19 15:00 | 26 | [178] Denis Kudla v Karlovic, Ivo [25] | 4-6,4-6 | |
| Wimbledon, London, Great Britain | 07/03 15:10 | 23 | [23] Karlovic, Ivo v Bedene, Aljaz [58] | 7-6,6-7,7-6,6-7,6-8 | |
| ATP Halle | 06/20 16:00 | 25 | [24] Karlovic, Ivo v Youzhny, Mikhail [88] | 3-6,6-7 | |
| ATP Den Bosch | 06/18 12:30 | 29 | [24] Karlovic, Ivo v Muller, Gilles [28] | 6-7,6-7 | |
| ATP Den Bosch | 06/17 15:10 | 28 | [7] Marin Cilic v Karlovic, Ivo [24] | 6-7,7-5,6-7 | |
| ATP Den Bosch | 06/16 11:05 | 27 | [24] Karlovic, Ivo v Daniil Medvedev [65] | 6-4,6-4 | |
| ATP Den Bosch | 06/15 09:00 | 26 | [24] Karlovic, Ivo v Stefan Kozlov [150] | 6-4,6-1 | |
| French Open, Paris, France | 05/31 10:50 | 24 | [24] Karlovic, Ivo v Zeballos, Horacio [65] | 6-7,6-7,3-6 | |
| French Open, Paris, France | 05/28 12:35 | 23 | [24] Karlovic, Ivo v Stefanos Tsitsipas [202] | 7-6,7-5,6-4 | |
| Rome, Italy | 05/16 08:00 | - | Karlovic, Ivo v HAAS T. | Cancelled | |
| ATP - Madrid | 05/10 18:20 | 25 | [12] Grigor Dimitrov v Karlovic, Ivo [22] | 6-3,7-5 | |
| ATP - Madrid | 05/09 10:00 | 24 | [22] Karlovic, Ivo v Bautista-Agut, Roberto [21] | 7-6,6-7,7-6 | |
| Budapest, Hongrie | 04/28 10:00 | 27 | [68] Bedene, Aljaz v Karlovic, Ivo [22] | 6-4,6-3 | |
| Budapest, Hongrie | 04/26 12:10 | 26 | [90] Damir Dzumhur v Karlovic, Ivo [22] | 1-6,6-3,4-6 | |
| ATP - Miami | 03/27 20:15 | 25 | [16] Kyrgios, Nick v Karlovic, Ivo [21] | 6-4,6-7,7-6 | |
| ATP - Miami | 03/25 21:20 | 24 | [68] Andrey Kuznetsov v Karlovic, Ivo [21] | 6-7,1-6 | |
| ATP - Indian Wells | 03/11 19:00 | 24 | [21] Karlovic, Ivo v Yoshihito Nishioka [70] | 4-6,3-6 |