| ATP Hamburg | 07/30 13:00 | 29 | [138] Leonardo Mayer v Florian Mayer [101] | 6-4,4-6,6-3 | |
| ATP Hamburg | 07/29 10:00 | 28 | [138] Leonardo Mayer v Federico Delbonis [81] | 6-3,7-5 | |
| ATP Hamburg | 07/28 11:40 | 27 | [138] Leonardo Mayer v Jiri Vesely [55] | 7-6,6-3 | |
| ATP Hamburg | 07/27 16:15 | 26 | [138] Leonardo Mayer v Jan-Lennard Struff [54] | 6-2,7-5 | |
| ATP Hamburg | 07/25 17:00 | 25 | [24] Albert Ramos-Vinolas v Leonardo Mayer [138] | 7-6,3-6,6-7 | |
| ATP Hamburg Qual | 07/23 12:40 | 46 | Rudolf Molleker v Leonardo Mayer | 7-6,3-6,6-3 | |
| ATP Hamburg Qual | 07/22 13:50 | 45 | Louis Wessels v Leonardo Mayer | 3-6,2-6 | |
| ATP Bastad | 07/18 11:40 | 25 | [89] Alexandr Dolgopolov v Leonardo Mayer [134] | 6-3,6-2 | |
| ATP Bastad Qual | 07/17 14:15 | 46 | [166] Paul-Henri Mathieu v Leonardo Mayer [134] | 6-2,3-6,2-6 | |
| ATP Bastad Qual | 07/17 09:00 | 45 | [225] Tristan Lamasine v Leonardo Mayer [134] | 6-7,7-6,2-6 | |
| Challenger Bastad | 07/15 11:00 | 29 | [79] Dusan Lajovic v Leonardo Mayer [152] | 6-2,7-6 | |
| Challenger Bastad | 07/14 10:55 | 28 | [152] Leonardo Mayer v Mikael Ymer [398] | 6-3,6-0 | |
| Challenger Bastad | 07/13 09:00 | 27 | [152] Leonardo Mayer v Henri Laaksonen [104] | 3-6,6-3,6-2 | |
| Challenger Bastad | 07/12 11:55 | 26 | [152] Leonardo Mayer v Filip Krajinovic [180] | 7-6,6-3 | |
| Challenger Bastad | 07/10 11:00 | 25 | [111] Casper Ruud v Leonardo Mayer [152] | 6-3,6-7,4-6 | |
| Challenger Vicenza | 06/01 13:30 | 26 | [154] Leonardo Mayer v Matteo Donati [231] | 6-3,1-6,2-6 | |
| Challenger Vicenza | 05/30 11:50 | 25 | [154] Leonardo Mayer v Inigo Cervantes [163] | 6-4,7-6 | |
| French Open Qual | 05/24 10:30 | 45 | [151] Reilly Opelka v Leonardo Mayer [154] | 5-7,7-6,6-3 | |
| French Open Qual | 05/22 10:15 | 44 | [154] Leonardo Mayer v Joao Souza [140] | 6-2,6-1 | |
| Challenger Savannah | 05/02 14:00 | 25 | [148] Leonardo Mayer v Christopher O'Connell [255] | 6-4,5-7,1-6 | |
| Challenger Tallahassee | 04/26 15:00 | 26 | [131] Leonardo Mayer v Blaz Rola [271] | 2-6,4-6 | |
| Challenger Tallahassee | 04/25 14:00 | 25 | [131] Leonardo Mayer v Jose Statham [399] | 6-4,6-2 | |
| Challenger Tallahassee | 04/25 14:00 | 25 | Leonardo Mayer v Aziz Dougaz | Cancelled | |
| Challenger Sarasota | 04/17 17:20 | 25 | [112] Adam Pavlasek v Leonardo Mayer [132] | 1-6,7-5,6-4 | |
| ATP Houston | 04/13 17:00 | 26 | [144] Leonardo Mayer v John Isner [23] | 7-6,6-7,3-6 | |
| ATP Houston | 04/12 19:05 | 25 | [144] Leonardo Mayer v Adam Pavlasek [98] | 5-7,6-2,6-1 | |
| ATP Houston Qual | 04/09 18:20 | 46 | [136] Denis Kudla v Leonardo Mayer [145] | 6-3,4-6,4-6 | |
| ATP Houston Qual | 04/08 21:20 | 45 | [175] Tim Smyczek v Leonardo Mayer [145] | 6-3,4-6,6-7 | |
| Challenger Buenos Aires | 03/19 16:15 | 29 | [141] Leonardo Mayer v Taro Daniel [119] | 7-5,3-6,4-6 | |
| Challenger Buenos Aires | 03/18 14:00 | 28 | [141] Leonardo Mayer v Tristan Lamasine [205] | 6-1,6-1 |