Stadium: Central Court Round: 29 Ground: Hardcourt indoor
| ATP Moscow MD | 2021/10/22 15:05 | Ivashka/Martinez v Brkic/Cacic | 4-6,6-4,8-10 |
| ATP Moscow MD | 2021/10/21 11:00 | Brkic/Cacic v Inglot/Skupski | 7-6,5-7,10-8 |
| ATP Moscow MD | 2021/10/18 11:00 | Brkic/Cacic v Bublik/Mannarino | 6-2,6-1 |
| ATP Sofia MD | 2021/10/01 09:00 | Gonzalez/Molteni v Brkic/Cacic | 6-7,6-2,10-4 |
| ATP Sofia MD | 2021/09/29 10:40 | Golubev/Nedovyesov v Brkic/Cacic | 3-6,7-6,7-10 |
| ATP Metz MD | 2021/09/24 13:35 | Nys/Rinderknech v Brkic/Cacic | 6-3,7-6 |
| ATP Metz MD | 2021/09/23 14:10 | Reese/Verbeek v Brkic/Cacic | 3-6,3-6 |
| ATP Metz MD | 2021/09/22 10:00 | Giron/Olivetti v Brkic/Cacic | 4-6,7-6,1-10 |
| ATP Moscow MD | 2021/10/23 09:00 | Heliovaara/Middelkoop v Behar/Escobar | 6-7,6-3,10-8 |
| ATP Moscow MD | 2021/10/21 15:05 | Heliovaara/Middelkoop v Khachanov/Rublev | 6-4,2-6,10-7 |
| ATP Moscow MD | 2021/10/20 13:40 | Heliovaara/Middelkoop v Karatsev/Muzaev | 6-4,6-4 |