# 2021 Zadar Open – Singles

This was the first edition of the tournament.
Nikola Milojević won the title after defeating Dimitar Kuzmanov 2–6, 6–2, 7–6$^{(7–5)}$ in the final.

## Seeds

* Gianluca Mager (quarterfinals)
* Sumit Nagal (quarterfinals)
* Nikola Milojević (champion)
* Blaž Rola (first round)
* Alessandro Giannessi (second round)
* Filip Horanský (first round)
* Enzo Couacaud (first round)
* Gian Marco Moroni (first round)

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

### Finals

| Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final | Final |
| | Lukáš Klein | 4 | 6 | 2 | | | | | |
| 3 | Nikola Milojević | 6 | 4 | 6 | | | | | |
| 3 | Nikola Milojević | 6 | 4 | 6 | 3 | Nikola Milojević | 2 | 6 | 7$^7$ |
| | | | | | | Dimitar Kuzmanov | 6 | 2 | 6$^5$ |
| | Dimitar Kuzmanov | 6 | 2 | | | Dimitar Kuzmanov | 6 | 2 | 6$^5$ |
| Q | Nerman Fatić | 2 | 0$^r$ | | | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | G Mager | 6 | 4 | 6 | | | | | | | | | | | | | | | |
| | I Sijsling | 4 | 6 | 4 | 1 | G Mager | 1 | 6 | 6 | | | | | | | | | | |
| Q | N Sánchez Izquierdo | 3 | 6 | 6 | Q | N Sánchez Izquierdo | 6 | 4 | 1 | | | | | | | | | | |
| WC | M Pecotić | 6 | 3 | 2 | | | | | | 1 | G Mager | 4 | 6 | 4 | | | | | |
| LL | V Orlov | 1 | 2 | | | | | | | | L Klein | 6 | 4 | 6 | | | | | |
| | L Klein | 6 | 6 | | | L Klein | 5 | 6 | 6 | | | | | | | | | | |
| | M Vrbenský | 6 | 6 | | | M Vrbenský | 7 | 3 | 1 | | | | | | | | | | |
| 7 | E Couacaud | 3 | 2 | | | | | | | | | | | | | L Klein | 4 | 6 | 2 |
| 3 | N Milojević | 7$^7$ | 6 | | | | | | | | | | | | 3 | N Milojević | 6 | 4 | 6 |
| | T-l Wu | 6$^4$ | 1 | | 3 | N Milojević | 6 | 6 | | | | | | | | | | | |
| | T Gabashvili | 2 | 6 | 3 | LL | I Nedelko | 2 | 1 | | | | | | | | | | | |
| LL | I Nedelko | 6 | 2 | 6 | | | | | | 3 | N Milojević | 7 | 6 | | | | | | |
| Q | M Bortolotti | 1 | 3 | | | | | | | | V Kopřiva | 5 | 4 | | | | | | |
| | V Kopřiva | 6 | 6 | | | V Kopřiva | 2 | 6 | 6 | | | | | | | | | | |
| Q | U Ignatik | 6 | 6 | | Q | U Ignatik | 6 | 1 | 3 | | | | | | | | | | |
| 6 | F Horanský | 1 | 3 | | | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 8 | GM Moroni | 4 | 4 | | | | | | | | | | | | | | | |
| | D Kuzmanov | 6 | 6 | | | D Kuzmanov | 6 | 6 | | | | | | | | | | |
| | Z Kolář | 6 | 6 | | | Z Kolář | 4 | 3 | | | | | | | | | | |
| | A Vatutin | 4 | 2 | | | | | | | | D Kuzmanov | 6 | 6 | | | | | |
| | B Kavčič | 6 | 6 | | | | | | | | B Kavčič | 4 | 1 | | | | | |
| | A Pellegrino | 3 | 1 | | | B Kavčič | 6 | 6 | | | | | | | | | | |
| | A Molčan | 6 | 6 | | | A Molčan | 2 | 1 | | | | | | | | | | |
| 4 | B Rola | 4 | 4 | | | | | | | | | | | | | D Kuzmanov | 6 | 2 |
| 5 | A Giannessi | 7 | 7 | | | | | | | | | | | | Q | N Fatić | 2 | 0$^r$ |
| | R Bonadio | 5 | 5 | | 5 | A Giannessi | 6$^4$ | 7 | 6$^6$ | | | | | | | | | |
| Q | N Fatić | 6 | 6 | | Q | N Fatić | 7$^7$ | 5 | 7$^8$ | | | | | | | | | |
| Alt | H Bourchier | 2 | 4 | | | | | | | Q | N Fatić | 5 | 6 | 7 | | | | |
| WC | F Ninčević | 4 | 6 | 6 | | | | | | 2 | S Nagal | 7 | 3 | 5 | | | | |
| WC | M Poljičak | 6 | 4 | 3 | WC | F Ninčević | 0 | 1 | | | | | | | | | | |
| | N Serdarušić | 6$^4$ | 4 | | 2 | S Nagal | 6 | 6 | | | | | | | | | | |
| 2 | S Nagal | 7$^7$ | 6 | | | | | | | | | | | | | | | |