| Qatar Open 2019, MS | 06/08 10:30 | 4 | Timo Boll v Karlsson, Mattias | L | 4-0 | |
| Qatar Open 2019, MS | 06/08 04:30 | 5 | Zhou, Kai v Karlsson, Mattias | W | 1-4 | |
| Qatar Open XD | 05/30 03:40 | 1 | Karlsson, Mattias v Liam Pitchford | L | 2-4 | |
| Qatar Open 2019, MS | 05/05 09:00 | 1 | Long Ma v Karlsson, Mattias | L | 3-0 | |
| Qatar Open 2019, MS | 05/04 16:30 | 1 | Karlsson, Mattias v Liam Pitchford | W | 3-2 | |
| Qatar Open 2019, MS | 05/03 16:00 | 1 | Chen, Chien-An v Karlsson, Mattias | W | 1-3 | |
| Qatar Open 2019, MS | 05/03 14:00 | 1 | Chuang, Chih-Yuan v Karlsson, Mattias | W | 0-3 | |
| Qatar Open 2019, MS | 05/01 15:30 | 1 | Karlsson, Mattias v Tokic, Bojan | W | 3-2 | |
| Qatar Open 2019, MS | 05/01 14:00 | 1 | Karlsson, Mattias v Darko Jorgic | W | 3-0 | |
| Qatar Open 2019, MS | 04/30 17:30 | 1 | Karlsson, Mattias v Timo Boll | L | 0-3 | |
| Qatar Open 2019, MS | 04/30 09:00 | 1 | Siu Hang Lam v Karlsson, Mattias | W | 1-3 | |
| Qatar Open 2019, MS | 04/29 11:30 | 1 | Hunor Szocs v Karlsson, Mattias | W | 1-3 | |
| German Open 2020, WD | 03/24 18:40 | 3 | Chun Ting Wong v Karlsson, Mattias | L | 4-1 | |
| German Open 2020, WD | 03/24 13:30 | 4 | Koki Niwa v Karlsson, Mattias | W | 1-4 | |
| German Open 2020, WD | 03/23 19:20 | 5 | Karlsson, Mattias v Hugo Calderano | W | 4-2 | |
| Qatar Open 2020, MS, Qualification | 03/09 14:10 | 4 | Karlsson, Mattias v Zhou, Yu | L | 1-4 | |
| Qatar Open 2020, MS, Qualification | 03/08 14:20 | 5 | Simon Gauzy v Karlsson, Mattias | W | 1-4 | |
| Qatar Open XD | 03/07 15:10 | 1 | Karlsson, Mattias v Woojin Jang | W | 4-3 | |
| Qatar Open XD | 03/06 13:50 | 1 | Karlsson, Mattias v Dingshuo Liu | W | 4-3 | |
| Qatar Open 2019, MS | 02/03 17:50 | 3 | Samsonov, Vladimir v Karlsson, Mattias | L | 4-1 | |
| Qatar Open 2019, MS | 02/03 11:30 | 4 | Karlsson, Mattias v Ruwen Filus | W | 4-1 | |
| Qatar Open XD | 01/18 13:40 | 5 | Kirill Gerassimenko v Karlsson, Mattias | L | 4-3 | |
| Qatar Open XD | 11/16 18:10 | 5 | Yang Wang v Karlsson, Mattias | L | 4-3 | |
| Qatar Open 2019, MS | 09/15 15:30 | 1 | Tokic, Bojan v Karlsson, Mattias | L | 3-0 | |
| Qatar Open 2019, MS | 09/15 14:30 | 1 | Darko Jorgic v Karlsson, Mattias | W | 0-3 | |
| Qatar Open XD | 07/05 09:10 | 4 | Karlsson, Mattias v Yoshida, Masaki | L | 2-4 | |
| Qatar Open XD | 07/04 06:00 | 5 | Karlsson, Mattias v Ueda, Jin | W | 4-1 | |
| Qatar Open XD | 06/16 04:50 | 5 | Karlsson, Mattias v Xu, Xin | L | 0-4 | |
| Qatar Open XD | 06/15 03:10 | 1 | Tzu-Yi Yang v Karlsson, Mattias | W | 0-4 | |
| Qatar Open 2019, MS | 06/02 17:30 | 5 | Karlsson, Mattias v Chun Ting Wong | L | 3-4 |