| French Open | 05/29 16:20 | 24 | [68] Leonardo Mayer v Diego Schwartzman [20] | 4-6,6-3,6-4,7-5 | |
| French Open | 05/26 15:00 | 23 | [105] Jiri Vesely v Leonardo Mayer [68] | 6-7,3-6,0-6 | |
| ATP Genewa | 05/21 10:00 | 25 | [70] Joao Sousa v Leonardo Mayer [68] | 6-2,6-7,6-4 | |
| ATP Madryt | 05/04 13:30 | 45 | [98] Hugo Dellien v Leonardo Mayer [62] | 6-2,6-4 | |
| ATP Estoril | 05/02 17:00 | 26 | [75] Malek Jaziri v Leonardo Mayer [62] | 7-6,6-1 | |
| ATP Estoril | 04/30 14:50 | 25 | [62] Leonardo Mayer v Dusan Lajovic [23] | 7-6,6-4 | |
| ATP Barcelona | 04/24 12:40 | 25 | [2] Rafael Nadal v Leonardo Mayer [63] | 6-7,6-4,6-2 | |
| ATP Barcelona | 04/22 09:00 | 24 | [80] Marius Copil v Leonardo Mayer [63] | 3-6,7-6,5-7 | |
| ATP Monte Carlo | 04/13 09:00 | 45 | [61] Leonardo Mayer v Alexei Popyrin [119] | 6-7,6-2,6-7 | |
| ATP Miami | 03/26 00:30 | 25 | [10] Stefanos Tsitsipas v Leonardo Mayer [62] | 6-4,6-4 | |
| ATP Miami | 03/23 15:00 | 24 | [62] Leonardo Mayer v Guido Pella [32] | 6-2,6-4 | |
| ATP Miami | 03/21 15:00 | 23 | [62] Leonardo Mayer v Mikael Ymer [198] | 4-6,6-3,6-4 | |
| ATP Indian Wells | 03/09 20:35 | 24 | [19] Gael Monfils v Leonardo Mayer [56] | 6-4,3-6,6-3 | |
| ATP Indian Wells | 03/08 04:55 | 23 | [59] Reilly Opelka v Leonardo Mayer [56] | 6-7,6-7 | |
| ATP Sao Paulo | 03/01 15:30 | 27 | [55] Leonardo Mayer v Christian Garin [92] | 6-4,4-6,4-6 | |
| ATP Sao Paulo | 02/27 18:35 | 26 | [55] Leonardo Mayer v Lorenzo Sonego [114] | 6-1,3-6,6-3 | |
| ATP Rio De Janeiro | 02/19 16:00 | 25 | [66] Jaume Munar v Leonardo Mayer [55] | 7-6,6-4 | |
| ATP Buenos Aires | 02/13 19:30 | 26 | [51] Leonardo Mayer v Guido Pella [50] | 4-6,6-1,6-7 | |
| ATP Buenos Aires | 02/12 17:30 | 25 | [43] Dusan Lajovic v Leonardo Mayer [51] | 3-6,6-7 | |
| ATP Cordoba | 02/06 00:15 | 25 | [49] Leonardo Mayer v Federico Delbonis [77] | 4-6,7-6,3-6 | |
| Australian Open | 01/17 03:00 | 24 | [13] Fabio Fognini v Leonardo Mayer [53] | 7-6,6-3,7-6 | |
| Australian Open | 01/15 00:00 | 23 | [45] Nicolas Jarry v Leonardo Mayer [53] | 6-7,6-7,6-4,3-6 | |
| ATP Auckland | 01/09 23:00 | 27 | [54] Leonardo Mayer v Tennys Sandgren [63] | 3-6,6-7 | |
| ATP Auckland | 01/09 00:15 | 26 | [54] Leonardo Mayer v Matteo Berrettini [52] | 5-7,7-6,6-3 | |
| ATP Auckland | 01/07 23:00 | 25 | [33] Steve Johnson v Leonardo Mayer [54] | 5-7,3-6 | |
| ATP Auckland | 01/06 23:00 | - | Roberto Bautista-Agut v Leonardo Mayer | Cancelled | |
| ATP Brisbane | 12/31 07:20 | 25 | [56] Leonardo Mayer v Miomir Kecmanovic [131] | 3-6,1-6 | |
| ATP - Bazylea | 10/23 19:30 | 25 | [54] Leonardo Mayer v Gilles Simon [32] | 3-6,3-6 | |
| ATP Antwerpia | 10/15 12:40 | 25 | [53] Leonardo Mayer v Vasek Pospisil [79] | 3-6,5-7 | |
| ATP Shanghai | 10/09 05:00 | 24 | [53] Leonardo Mayer v Richard Gasquet [25] | 6-1,2-6,1-6 |