| ATP Hamburg | 07/22 09:30 | 25 | [415] Daniel Altmaier v Martin Klizan [62] | 2-6,2-6 | |
| ATP Umag | 07/16 14:00 | 25 | [61] Martin Klizan v Facundo Bagnis [152] | 6-4,3-6,5-7 | |
| Wimbledon | 07/01 15:10 | 23 | [81] Jeremy Chardy v Martin Klizan [56] | 3-6,6-0,6-3,6-4 | |
| Boodles Challenge | 06/29 15:00 | 1 | [54] Martin Klizan v Dusan Lajovic [33] | 3-6,2-6 | |
| Boodles Challenge | 06/27 16:40 | 1 | [51] Filip Krajinovic v Martin Klizan [54] | 6-4,7-6 | |
| Boodles Challenge | 06/25 15:55 | 1 | [24] Diego Schwartzman v Martin Klizan [54] | 6-3,5-7,5-10 | |
| Challenger Bratislava | 06/20 16:25 | 26 | [56] Martin Klizan v Sumit Nagal [251] | 6-1,1-6,6-7 | |
| Challenger Bratislava | 06/19 16:00 | 25 | Martin Klizan v Lucas Gerch | 6-4,7-5 | |
| French Open | 06/01 15:15 | 25 | [11] Karen Khachanov v Martin Klizan [55] | 6-1,6-4,6-3 | |
| French Open | 05/30 15:55 | 24 | [55] Martin Klizan v Lucas Pouille [26] | 7-6,2-6,6-3,3-6,9-7 | |
| French Open | 05/28 12:35 | 23 | [55] Martin Klizan v Mikhail Kukushkin [51] | 3-6,5-7,6-4,6-2,6-3 | |
| ATP Lyon | 05/20 09:00 | 25 | [59] Steve Johnson v Martin Klizan [54] | Cancelled | |
| ATP Rome | 05/11 16:45 | 45 | [158] Filippo Baldi v Martin Klizan [61] | 6-3,6-1 | |
| ATP Madrid | 05/06 14:10 | 24 | [11] Marin Cilic v Martin Klizan [61] | 6-4,2-6,7-6 | |
| ATP Madrid | 05/05 14:35 | 46 | [56] Adrian Mannarino v Martin Klizan [60] | 3-6,2-6 | |
| ATP Madrid | 05/04 16:55 | 45 | [78] Ernests Gulbis v Martin Klizan [60] | 4-6,6-7 | |
| ATP Munich | 05/01 13:00 | 26 | [19] Marco Cecchinato v Martin Klizan [60] | 6-1,6-3 | |
| ATP Munich | 04/30 10:50 | 25 | [78] Ernests Gulbis v Martin Klizan [60] | 3-6,5-7 | |
| ATP Barcelona | 04/23 13:15 | 24 | [47] Martin Klizan v Christian Garin [48] | 5-7,4-6 | |
| ATP Monte Carlo | 04/17 14:25 | 25 | [5] Dominic Thiem v Martin Klizan [50] | 6-1,6-4 | |
| ATP Monte Carlo | 04/15 12:35 | 24 | [74] Federico Delbonis v Martin Klizan [50] | 6-7,5-7 | |
| ATP Miami | 03/21 16:55 | 23 | [48] Martin Klizan v Lorenzo Sonego [106] | 4-6,3-6 | |
| ATP Indian Wells | 03/10 01:00 | 24 | [3] Alexander Zverev v Martin Klizan [50] | Retired | |
| ATP Indian Wells | 03/07 19:00 | 23 | [50] Martin Klizan v Mischa Zverev [75] | 6-1,6-4 | |
| ATP Rotterdam | 02/13 10:00 | 25 | [39] Martin Klizan v Marton Fucsovics [38] | 6-7,4-6 | |
| ATP Sofia | 02/08 16:00 | 27 | [38] Martin Klizan v Daniil Medvedev [16] | 4-6,1-6 | |
| ATP Sofia | 02/07 10:00 | 26 | [180] Daniel Brands v Martin Klizan [38] | 6-7,4-6 | |
| ATP Sofia | 02/06 10:00 | 25 | [99] Mirza Basic v Martin Klizan [38] | 0-6,6-3,2-6 | |
| Davis Cup | 02/02 12:05 | - | [38] Martin Klizan v Denis Shapovalov [25] | 6-7,4-6 | |
| Davis Cup | 02/01 15:45 | - | [38] Martin Klizan v Felix Auger Aliassime [106] | 7-5,6-3 |