Stadium: Court 1 Round: 28 Ground: Clay
| Challenger Belgrade MD | 2021/04/15 17:00 | Jebavy/Zelenay v Brkic/Cacic | 6-7,3-6 |
| Challenger Belgrade MD | 2021/04/15 09:00 | Troicki/Zekic v Brkic/Cacic | 4-6,2-6 |
| ATP Marbella MD | 2021/04/11 10:00 | Behar/Escobar v Brkic/Cacic | 6-2,6-4 |
| ATP Marbella MD | 2021/04/09 12:00 | Arevalo/Middelkoop v Brkic/Cacic | 4-6,4-6 |
| ATP Marbella MD | 2021/04/07 15:15 | Brkic/Cacic v Daniell/Oswald | 4-6,7-6,11-9 |
| ATP Marbella MD | 2021/04/06 13:55 | Brkic/Cacic v Arends/Pel | 1-6,6-0,10-5 |
| ATP Santiago MD | 2021/03/10 20:00 | Bolelli/Gonzalez v Brkic/Cacic | 7-6,6-3 |
| ATP Buenos Aires MD | 2021/03/07 16:00 | Behar/Escobar v Brkic/Cacic | 3-6,5-7 |
| Challenger Belgrade MD | 2021/04/15 19:25 | Goransson/O'Mara v Bagnis/Cerundolo | 3-6,3-6 |
| Challenger Belgrade MD | 2021/04/14 16:55 | Bagnis/Cerundolo v Bambridge/Inglot | 4-6,7-6,11-9 |