| Challenger Ortisei | 10/23 13:30 | 14 | Evgeny Karlovskiy v Lacko, Lukas | Retired | |
| Challenger Ismaning | 10/09 17:55 | 14 | [342] Bu Yunchaokete v Lacko, Lukas [495] | 3-6,6-2,6-3 | |
| Challenger Mallorca | 08/30 09:45 | 19 | Lacko, Lukas v Daniil Glinka | Retired | |
| Challenger Mallorca | 08/29 09:50 | 14 | [327] Lacko, Lukas v Alexander Donski [291] | 6-4,6-4 | |
| Challenger Malaga | 06/28 10:45 | 25 | [405] Marcora, Roberto v Lacko, Lukas [301] | 4-6,6-4,6-4 | |
| Wimbledon, London, Great Britain | 06/20 11:05 | 14 | [187] Martin, Andrej v Lacko, Lukas [296] | 6-2,6-1 | |
| Ilkley, Great Britain | 06/13 10:00 | 19 | [238] Lacko, Lukas v Rinky Hijikata [230] | 6-3,3-6,4-6 | |
| Ilkley, Great Britain | 06/12 13:25 | 14 | [204] Alexander Ritschard v Lacko, Lukas [242] | 3-6,2-6 | |
| Challenger - Nottingham | 06/06 16:40 | 25 | [100] Alexei Popyrin v Lacko, Lukas [242] | 6-4,6-2 | |
| Prostejov, Czech Republic | 05/31 11:50 | 25 | Lacko, Lukas v Lukas Pokorny | Cancelled | |
| Troisdorf, Germany | 05/24 14:45 | 25 | [386] Aldin Setkic v Lacko, Lukas [229] | 4-6,6-3,6-4 | |
| French Open, Paris, France | 05/17 08:00 | 14 | [229] Lacko, Lukas v Nicolas Jarry [138] | 6-7,3-6 | |
| Challenger Zagreb | 05/10 11:45 | 25 | [225] Lacko, Lukas v Filip Misolic [301] | 4-6,1-6 | |
| Mauthausen, Austria | 05/02 15:10 | 25 | [157] Jurij Rodionov v Lacko, Lukas [224] | 6-1,6-0 | |
| Challenger - Ostrava | 04/26 13:50 | 25 | [278] Evan Furness v Lacko, Lukas [220] | 6-1,6-1 | |
| Forli 6, Italy | 02/22 11:35 | 25 | [132] Tomas Machac v Lacko, Lukas [207] | 6-2,6-2 | |
| ATP - Marseille | 02/13 10:00 | 14 | [252] Arnaboldi, Andrea v Lacko, Lukas [206] | 7-6,6-4 | |
| ATP - Montpellier | 01/30 13:10 | 14 | Lacko, Lukas v Antoine Hoang | 6-7,2-6 | |
| ATP - Montpellier | 01/30 13:10 | 14 | [188] Lacko, Lukas v Moraing, Mats [156] | Cancelled | |
| Challenger - Quimper | 01/27 17:00 | 27 | [138] Vasek Pospisil v Lacko, Lukas [188] | 6-4,6-3 | |
| Challenger - Quimper | 01/25 17:05 | 25 | [156] Moraing, Mats v Lacko, Lukas [188] | 3-6,5-7 | |
| Forli 6, Italy | 01/18 14:40 | 25 | [221] Andrea Pellegrino v Lacko, Lukas [188] | 0-6,6-3,7-6 | |
| Open d'Australie | 01/09 23:00 | 14 | [199] Marco Trungelliti v Lacko, Lukas [190] | 6-3,6-4 | |
| Czech Extraliga, Men | 12/14 10:20 | - | Dominik Kellovsky v Lacko, Lukas | 4-6,4-6 | |
| Czech Extraliga, Men | 12/13 11:40 | - | [142] Zdenek Kolar v Lacko, Lukas [190] | 6-3,7-5 | |
| Challenger Bratislava | 11/11 17:20 | 26 | [195] Lacko, Lukas v Zsombor Piros [340] | 2-6,4-6 | |
| Challenger Bratislava | 11/10 13:50 | 25 | Milos Karol v Lacko, Lukas | 4-6,3-6 | |
| Challenger Eckental | 11/03 09:00 | 25 | Ramkumar Ramanathan v Lacko, Lukas | Cancelled | |
| Challenger Ismaning | 10/31 13:00 | 29 | [212] Lacko, Lukas v Oscar Otte [135] | 4-6,4-6 | |
| Challenger Ismaning | 10/30 14:10 | 28 | [148] Quentin Halys v Lacko, Lukas [212] | 1-6,6-7 |