| ITF M25 Maceio | 03/21 01:25 | 25 | Mateus Alves v Gabriel P Tumasonis | 6-1,6-2 | |
| ITF M25 Maceio | 03/18 15:00 | 54 | Facundo Bermejo v Gabriel P Tumasonis | 5-7,2-6 | |
| ITF M25 Feira De Santana | 03/10 13:00 | 54 | Joaquim Almeida v Gabriel P Tumasonis | Retired | |
| ITF M25 Recife | 03/06 14:40 | 25 | Gabriel P Tumasonis v Quentin Folliot | 4-6,6-4,4-6 | |
| ITF M25 Recife | 03/04 15:15 | 54 | Facundo Bermejo v Gabriel P Tumasonis | 0-6,6-7 | |
| ITF M25 Recife | 03/03 16:00 | 54 | Guilherme Meale v Gabriel P Tumasonis | 0-6,2-6 | |
| Challenger Piracicaba | 01/28 18:45 | 14 | Damien Wenger v Gabriel Tumasonis | 6-1,6-1 | |
| ITF M25 Lajeado | 10/09 16:00 | 54 | Sean Hess v Gabriel P Tumasonis | 6-3,6-2 | |
| ITF M15 Sao Paulo | 08/21 16:30 | 54 | Enzo Lima v Gabriel P Tumasonis | 6-3,6-1 | |
| ITF M15 Belem | 08/15 13:00 | 54 | Gabriel P Tumasonis v Miguel Angel Cabrera | 0-6,1-6 | |
| ITF M15 Belem | 08/14 13:00 | 54 | Gabriel P Tumasonis v Valentin M Greco | 6-3,6-3 | |
| ITF M25 Mosquera | 03/20 18:40 | 54 | Arvid Nordquist v Gabriel P Tumasonis | 6-3,6-4 | |
| ITF M25 Anapoima | 03/12 15:00 | 54 | Joel Angel Lucero v Gabriel P Tumasonis | 6-1,6-2 | |
| ITF M25 Santo Domingo | 02/20 14:00 | 62 | Ziwen Ju v Gabriel P Tumasonis | 7-6,6-3 | |
| ITF M25 Santo Domingo Qual | 02/19 13:00 | 62 | Liam Oliver v Gabriel P Tumasonis | 6-3,4-6,6-10 | |
| ITF M25 Santo Domingo | 02/14 13:00 | 62 | Gabriel P Tumasonis v Thomas Brown | 3-6,1-6 | |
| ITF M25 Santo Domingo | 02/13 17:00 | 62 | Gabriel P Tumasonis v Kenzo K Larsson | 7-5,6-4 | |
| ITF M25 Vacaria | 11/30 16:05 | 25 | Gabriel P Tumasonis v Gabriel Schenekenberg | 4-6,6-7 | |
| ITF M25 Lajeado | 11/22 23:10 | 25 | Lorenzo Joaquin Rodriguez v Gabriel P Tumasonis | 6-3,6-3 | |
| Challenger Sao Leopoldo | 11/13 14:15 | 14 | Gabriel P Tumasonis v Eduardo Ribeiro | 3-6,5-7 | |
| ITF M25 Rio de Janeiro | 10/19 17:30 | 25 | Pedro Rodrigues v Gabriel P Tumasonis | 6-4,6-2 | |
| Challenger Campinas | 10/02 14:30 | 14 | Carlos Sanchez Jover v Gabriel P Tumasonis | 6-1,6-1 | |
| ITF M15 Cancun | 10/01 15:00 | 26 | Andres Andrade v Gabriel P Tumasonis | Cancelled | |
| ITF M15 Cancun | 09/28 14:00 | 25 | Gabriel P Tumasonis v Andrew Rogers | 3-6,4-6 | |
| ITF M15 Cancun | 09/20 15:00 | 25 | Gabriel P Tumasonis v Joao M Nusdeo | 6-3,1-6,4-6 | |
| ITF M15 Cancun | 09/20 15:00 | 25 | Gabriel P Tumasonis v Jaden Weekes | Cancelled | |
| ITF M15 Cancun | 09/13 20:10 | 25 | Gabriel Tumasonis v Mwendwa Mbithi | 6-7,2-6 | |
| ITF M15 Cancun | 09/08 14:00 | 26 | Victor Lilov v Gabriel Tumasonis | 6-4,6-3 | |
| ITF M15 Cancun | 09/07 15:40 | 25 | Gabriel Tumasonis v Kosuke Ogura | 6-2,6-3 | |
| ITF M15 Brasilia | 08/25 13:00 | 26 | Fernando Yamacita v Gabriel P Tumasonis | 6-2,7-6 |