| Polish Open | 10/18 12:20 | - | Jiri Martinko v Monteiro, Thiago | W | 3-4 | |
| German Open 2020, MS | 10/08 17:35 | - | Hon Ming Li v Monteiro, Thiago | W | 2-4 | |
| Swedish Open (WTP) 2019, MS, Qualification | 10/01 14:10 | - | Monteiro, Thiago v Zhang, Yudong | L | 1-4 | |
| Paraguay Open | 09/13 23:35 | - | Monteiro, Thiago v Masataka Morizono | L | 1-4 | |
| Paraguay Open | 09/13 16:35 | - | Monteiro, Thiago v Marcos Madrid | W | 4-0 | |
| Bulgaria Open 2019, MS | 08/15 17:10 | 5 | Monteiro, Thiago v Chun Ting Wong | L | 2-4 | |
| ITTF China Open 2019, MS | 05/28 09:00 | - | Ibrahim Gunduz v Monteiro, Thiago | W | 2-4 | |
| World Championship | 04/23 13:00 | 57 | Monteiro, Thiago v Marcos Freitas | L | 1-4 | |
| Qatar Open 2019, MS | 03/28 17:05 | 5 | Woojin Jang v Monteiro, Thiago | L | 4-2 | |
| Qatar Open XD | 03/27 15:00 | - | Monteiro, Thiago v Cheng-Ting Liao | W | 4-1 | |
| Qatar Open XD | 03/26 14:20 | - | Quadri Aruna v Monteiro, Thiago | W | 1-4 | |
| Qatar Open XD | 01/15 17:50 | - | Wei, Shihao v Monteiro, Thiago | L | 4-2 | |
| Qatar Open XD | 08/22 11:20 | - | Burov, Viacheslav v Monteiro, Thiago | L | 4-3 | |
| Qatar Open XD | 08/22 08:00 | 1 | Monteiro, Thiago v Frane Kojic | W | 4-3 | |
| Qatar Open XD | 08/21 12:10 | 1 | Monteiro, Thiago v Cho, Eonrae | W | 4-2 | |
| Qatar Open XD | 08/15 13:00 | 1 | Monteiro, Thiago v Zhao, Zihao | L | 1-4 | |
| Qatar Open XD | 08/15 07:10 | - | Monteiro, Thiago v Marco Rech Daldosso | W | 4-0 | |
| Qatar Open XD | 05/18 04:55 | 1 | Lai, Jiaxin v Monteiro, Thiago | W | 1-4 | |
| Qatar Open XD | 11/02 18:10 | 1 | Monteiro, Thiago v Kim, Donghyun | L | 0-4 | |
| Qatar Open XD | 11/11 19:30 | 5 | Monteiro, Thiago v Kwan Kit Ho | L | 0-4 | |
| Qatar Open XD | 11/11 15:10 | 6 | Baum, Patrick v Monteiro, Thiago | W | 0-4 | |
| Qatar Open 2019, MS | 09/22 12:49 | - | Monteiro, Thiago v Jonas Stener | W | 4-3 |