# 2021 Amex-Istanbul Challenger – Singles

Ilya Ivashka was the defending champion but chose not to defend his title.
Arthur Rinderknech won the title after defeating Benjamin Bonzi 4–6, 7–6$^{(7–1)}$, 7–6$^{(7–3)}$ in the final.

## Seeds

* Daniel Elahi Galán (first round)
* Thiago Seyboth Wild (first round)
* Antoine Hoang (quarterfinals)
* Facundo Bagnis (second round)
* Prajnesh Gunneswaran (first round, retired)
* Lorenzo Musetti (second round)
* Jozef Kovalík (semifinals)
* Go Soeda (quarterfinals, withdrew)

## 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 | Final |
| 7 | Jozef Kovalík | 5 | 4 | | | | | |
| Q | Arthur Rinderknech | 7 | 6 | | | | | |
| Q | Arthur Rinderknech | 7 | 6 | Q | Arthur Rinderknech | 4 | 7$^7$ | 7$^7$ |
| | | | | | Benjamin Bonzi | 6 | 6$^1$ | 6$^3$ |
| | Benjamin Bonzi | 7$^7$ | 6 | | Benjamin Bonzi | 6 | 6$^1$ | 6$^3$ |
| | Mohamed Safwat | 6$^1$ | 4 | | | | | |

### 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 | DE Galán | 6$^5$ | 3 | | | | | | | | | | | | | | | |
| Q | J Menezes | 7$^7$ | 6 | | Q | J Menezes | 2 | 6$^5$ | | | | | | | | | | |
| WC | E Kırkın | 6 | 6 | | WC | E Kırkın | 6 | 7$^7$ | | | | | | | | | | |
| | P Lorenzi | 4 | 2 | | | | | | | WC | E Kırkın | 7$^7$ | 0 | 6$^3$ | | | | |
| | B Zapata Miralles | 4 | 2 | | | | | | | 7 | J Kovalík | 6$^5$ | 6 | 7$^7$ | | | | |
| | C Taberner | 6 | 6 | | | C Taberner | 6$^4$ | 0 | | | | | | | | | | |
| WC | A Çelikbilek | 5 | 6 | 4 | 7 | J Kovalík | 7$^7$ | 6 | | | | | | | | | | |
| 7 | J Kovalík | 7 | 2 | 6 | | | | | | | | | | | 7 | J Kovalík | 5 | 4 |
| 4 | F Bagnis | 6 | 6 | | | | | | | | | | | | Q | A Rinderknech | 7 | 6 |
| | Zh Zhang | 4 | 1 | | 4 | F Bagnis | 5 | 2 | | | | | | | | | | |
| | M-A Hüsler | 2 | 6 | 6 | | M-A Hüsler | 7 | 6 | | | | | | | | | | |
| LL | D Istomin | 6 | 2 | 4 | | | | | | | M-A Hüsler | 5 | 3 | | | | | |
| | B Nakashima | 3 | 6 | 6 | | | | | | Q | A Rinderknech | 7 | 6 | | | | | |
| WC | C İlkel | 6 | 4 | 3 | | B Nakashima | 7$^9$ | 1 | 4 | | | | | | | | | |
| Q | A Rinderknech | 6 | 3 | | Q | A Rinderknech | 6$^7$ | 6 | 6 | | | | | | | | | |
| 5 | P Gunneswaran | 4 | 2$^r$ | | | | | | | | | | | | | | | |

### 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 |
| 6 | L Musetti | 6 | 7$^8$ | | | | | | | | | | | | | | |
| | D Petrović | 4 | 6$^6$ | | 6 | L Musetti | 1 | 4 | | | | | | | | | |
| | B Rola | 4 | 1$^r$ | | | B Bonzi | 6 | 6 | | | | | | | | | |
| | B Bonzi | 6 | 2 | | | | | | | | B Bonzi | 6$^5$ | 6 | 7 | | | |
| | L Giustino | 7 | 7$^7$ | | | | | | | 3 | A Hoang | 7$^7$ | 1 | 5 | | | |
| | A Giannessi | 5 | 6$^5$ | | | L Giustino | 4 | 4 | | | | | | | | | |
| | E Gómez | 7$^7$ | 2 | 4 | 3 | A Hoang | 6 | 6 | | | | | | | | | |
| 3 | A Hoang | 6$^3$ | 6 | 6 | | | | | | | | | | | B Bonzi | 7$^7$ | 6 |
| 8 | G Soeda | 6 | 6 | | | | | | | | | | | | M Safwat | 6$^1$ | 4 |
| | A Tabilo | 3 | 3 | | 8 | G Soeda | 7 | 4 | 7$^7$ | | | | | | | | |
| Q | L Rosol | 4 | 6$^3$ | | | T Griekspoor | 5 | 6 | 6$^2$ | | | | | | | | |
| | T Griekspoor | 6 | 7$^7$ | | | | | | | 8 | G Soeda | | | | | | |
| Q | J Clarke | 3 | 5 | | | | | | | | M Safwat | w/o | | | | | |
| | F Gaio | 6 | 7 | | | F Gaio | 6$^4$ | 5 | | | | | | | | | |
| | M Safwat | 6 | 6 | | | M Safwat | 7$^7$ | 7 | | | | | | | | | |
| 2 | T Seyboth Wild | 4 | 1 | | | | | | | | | | | | | | |