# 2021 Lošinj Open – Singles

This was the first edition of the tournament.
Carlos Taberner won the title by walkover after Marco Cecchinato withdrew before the final.

## Seeds

* Marco Cecchinato (final, withdrew)
* Carlos Taberner (champion)
* Andrej Martin (second round)
* Nikola Milojević (first round)
* Blaž Rola (first round)
* Alessandro Giannessi (semifinals)
* Jay Clarke (first round)
* Mathias Bourgue (quarterfinals)

## 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 | Final | Final | Final |
| 1 | Marco Cecchinato | 6 | 7$^7$ | | | |
| | Nerman Fatić | 3 | 6$^4$ | | | |
| | Nerman Fatić | 3 | 6$^4$ | 1 | Marco Cecchinato | |
| | | | | 2 | Carlos Taberner | w/o |
| 6 | Alessandro Giannessi | 4 | 3 | 2 | Carlos Taberner | w/o |
| 2 | Carlos Taberner | 6 | 6 | | | |

### 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 |
| 1 | M Cecchinato | 7$^7$ | 7$^7$ | | | | | | | | | | | | | | | |
| Alt | Á López San Martín | 6$^5$ | 6$^2$ | | 1 | M Cecchinato | 6$^4$ | 7$^7$ | 6 | | | | | | | | | |
| | M Guinard | 6 | 3 | 4 | | N Serdarušić | 7$^7$ | 6$^4$ | 1 | | | | | | | | | |
| | N Serdarušić | 2 | 6 | 6 | | | | | | 1 | M Cecchinato | 6 | 2 | 7 | | | | |
| Alt | A Šetkić | 6 | 6 | | | | | | | 8 | M Bourgue | 0 | 6 | 5 | | | | |
| WC | Anthony Genov | 3 | 4 | | Alt | A Šetkić | 0 | 2 | | | | | | | | | | |
| | D Petrović | 2$^r$ | | | 8 | M Bourgue | 6 | 6 | | | | | | | | | | |
| 8 | M Bourgue | 5 | | | | | | | | | | | | | 1 | M Cecchinato | 6 | 7$^7$ |
| 3 | A Martin | 7$^7$ | 6 | | | | | | | | | | | | | N Fatić | 3 | 6$^4$ |
| WC | M Poljičak | 6$^2$ | 3 | | 3 | A Martin | 1 | 6$^{11}$ | | | | | | | | | | |
| Q | F Misolic | 6 | 6 | | Q | F Misolic | 6 | 7$^{13}$ | | | | | | | | | | |
| Q | A Kadhe | 1 | 2 | | | | | | | Q | F Misolic | 6$^6$ | 2 | | | | | |
| Q | N Álvarez Varona | 5 | 2 | | | | | | | | N Fatić | 7$^8$ | 6 | | | | | |
| | N Fatić | 7 | 6 | | | N Fatić | 6 | 2 | 6 | | | | | | | | | |
| Q | Georgii Kravchenko | 6 | 6 | | Q | G Kravchenko | 3 | 6 | 3 | | | | | | | | | |
| 5 | B Rola | 4 | 2 | | | | | | | | | | | | | | | |

### 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 |
| 6 | A Giannessi | 7$^7$ | 7 | | | | | | | | | | | | | | | |
| | R Haase | 6$^4$ | 5 | | 6 | A Giannessi | 7$^9$ | 3 | 6 | | | | | | | | | |
| | D Ajduković | 6$^2$ | 0 | | | F Agamenone | 6$^7$ | 6 | 1 | | | | | | | | | |
| | F Agamenone | 7$^7$ | 6 | | | | | | | 6 | A Giannessi | 6 | 6$^6$ | 6 | | | | |
| Alt | R Brancaccio | 6 | 3 | 6 | | | | | | Alt | R Brancaccio | 3 | 7$^8$ | 1 | | | | |
| | E Kırkın | 3 | 6 | 2 | Alt | R Brancaccio | 6 | 6 | | | | | | | | | | |
| | C Gimeno Valero | 6 | 6 | | | C Gimeno Valero | 4 | 1 | | | | | | | | | | |
| 4 | N Milojević | 3 | 1 | | | | | | | | | | | | 6 | A Giannessi | 4 | 3 |
| 7 | J Clarke | 3 | 6 | 3 | | | | | | | | | | | 2 | C Taberner | 6 | 6 |
| | A Arnaboldi | 6 | 3 | 6 | | A Arnaboldi | 6 | 3 | 6 | | | | | | | | | |
| | J Forejtek | 6 | 6 | | | J Forejtek | 3 | 6 | 4 | | | | | | | | | |
| WC | VV Cornea | 4 | 4 | | | | | | | | A Arnaboldi | 2 | 0 | | | | | |
| | G Blancaneaux | 6 | 6 | | | | | | | 2 | C Taberner | 6 | 6 | | | | | |
| | FC Jianu | 2 | 3 | | | G Blancaneaux | 6$^1$ | 6 | 1 | | | | | | | | | |
| | J Barranco Cosano | 4 | 3 | | 2 | C Taberner | 7$^7$ | 3 | 6 | | | | | | | | | |
| 2 | C Taberner | 6 | 6 | | | | | | | | | | | | | | | |