# 2021 Antalya Challenger III – Singles

Carlos Taberner was the defending champion but was not eligible to compete in the tournament due to his ATP ranking.
Nuno Borges won the title after defeating Ryan Peniston 6–4, 6–3 in the final.

## Seeds

* Cem İlkel (second round)
* Ramkumar Ramanathan (quarterfinals)
* João Domingues (second round)
* Duje Ajduković (quarterfinals)
* Tseng Chun-hsin (first round)
* Nuno Borges (champion)
* Geoffrey Blancaneaux (second round)
* Gonçalo Oliveira (first round, retired)

## 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 | Final |
| | Javier Barranco Cosano | 4 | 6$^2$ | | | | |
| | Ryan Peniston | 6 | 7$^7$ | | | | |
| | Ryan Peniston | 6 | 7$^7$ | | Ryan Peniston | 4 | 3 |
| | | | | 6 | Nuno Borges | 6 | 6 |
| 6 | Nuno Borges | 6 | 6 | 6 | Nuno Borges | 6 | 6 |
| | Eduard Esteve Lobato | 3 | 3 | | | | |

### 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 |
| 1/WC | C İlkel | 6 | 6 | | | | | | | | | | | | | | |
| Alt | Y-h Hsu | 3 | 4 | | 1/WC | C İlkel | 6$^3$ | 3 | | | | | | | | | |
| | J Barranco Cosano | 7$^7$ | 6 | | | J Barranco Cosano | 7$^7$ | 6 | | | | | | | | | |
| | O Roca Batalla | 6$^4$ | 4 | | | | | | | | J Barranco Cosano | 6 | 4 | 6 | | | |
| Q | M Veldheer | 1 | 4 | | | | | | | | FC Jianu | 1 | 6 | 4 | | | |
| | FC Jianu | 6 | 6 | | | FC Jianu | 6$^5$ | 6 | 6 | | | | | | | | |
| | M Zekić | 6$^2$ | 3 | | 7 | G Blancaneaux | 7$^7$ | 4 | 0 | | | | | | | | |
| 7 | G Blancaneaux | 7$^7$ | 6 | | | | | | | | | | | | J Barranco Cosano | 4 | 6$^2$ |
| 4 | D Ajduković | 6 | 5 | 7 | | | | | | | | | | | R Peniston | 6 | 7$^7$ |
| | N Chappell | 4 | 7 | 5 | 4 | D Ajduković | 6 | 6 | | | | | | | | | |
| Q | T Cação | 6 | 6 | | Q | T Cação | 2 | 1 | | | | | | | | | |
| WC | A Metreveli | 3 | 2 | | | | | | | 4 | D Ajduković | 2 | 7 | 6$^2$ | | | |
| | R Peniston | 2 | 6 | 6 | | | | | | | R Peniston | 6 | 5 | 7$^7$ | | | |
| | N Fatić | 6 | 1 | 3 | | R Peniston | 2 | 6 | 6 | | | | | | | | |
| | D Svrčina | 6 | 0 | | | D Svrčina | 6 | 4 | 2 | | | | | | | | |
| 8 | G Oliveira | 4 | 0$^r$ | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 6 | N Borges | 6 | 6 | | | | | | | | | | | | | |
| | E Kırkın | 4 | 3 | | 6 | N Borges | 6 | 6 | | | | | | | | |
| | E Tiurnev | 6$^5$ | 7 | 3$^r$ | WC | Y Erel | 4 | 0 | | | | | | | | |
| WC | Y Erel | 7$^7$ | 5 | 3 | | | | | 6 | N Borges | 6 | 6 | | | | |
| | N Hardt | 6 | 6 | | | | | | | N Hardt | 2 | 4 | | | | |
| | A Dougaz | 2 | 2 | | | N Hardt | 6 | 7 | | | | | | | | |
| | R Bonadio | 6$^4$ | 6 | 1 | 3 | J Domingues | 4 | 5 | | | | | | | | |
| 3 | J Domingues | 7$^7$ | 4 | 6 | | | | | | | | | 6 | N Borges | 6 | 6 |
| 5 | C-h Tseng | 2 | 7 | 6$^7$ | | | | | | | | | | E Esteve Lobato | 3 | 3 |
| | F Misolic | 6 | 5 | 7$^9$ | | F Misolic | 2 | 3 | | | | | | | | |
| Alt | D-h Lee | 2 | 3 | | | E Esteve Lobato | 6 | 6 | | | | | | | | |
| | Eduard Esteve Lobato | 6 | 6 | | | | | | | E Esteve Lobato | 6 | 6 | | | | |
| | N Sánchez Izquierdo | 1 | 3 | | | | | | 2 | R Ramanathan | 2 | 0 | | | | |
| Q | O Crawford | 6 | 6 | | Q | O Crawford | 5 | 4 | | | | | | | | |
| Q | L Wessels | 2 | 3 | | 2 | R Ramanathan | 7 | 6 | | | | | | | | |
| 2 | R Ramanathan | 6 | 6 | | | | | | | | | | | | | |