# 2021 Città di Forlì III – Singles

Maxime Cressy was the defending champion but lost in the quarterfinals to Vitaliy Sachko.
Pavel Kotov won the title after defeating Andrea Arnaboldi 6–4, 6–3 in the final.

## Seeds

* Maxime Cressy (quarterfinals)
* Federico Gaio (first round)
* Salvatore Caruso (first round)
* Zizou Bergs (first round)
* Mirza Bašić (quarterfinals)
* Vitaliy Sachko (semifinals, retired)
* Andrea Vavassori (first round)
* Andrea Arnaboldi (final)

## 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 |
| 6 | Vitaliy Sachko | 4 | 0$^r$ | | | | | |
| | Pavel Kotov | 6 | 4 | | | | | |
| | Pavel Kotov | 6 | 4 | | | Pavel Kotov | 6 | 6 |
| | | | | | 8 | Andrea Arnaboldi | 4 | 3 |
| 8 | Andrea Arnaboldi | 4 | 6 | 6 | 8 | Andrea Arnaboldi | 4 | 3 |
| WC | Luca Nardi | 6 | 3 | 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 | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | M Cressy | 6 | 6 | | | | | | | | | | | | | | |
| | J Sels | 3 | 2 | | 1 | M Cressy | 7$^7$ | 6 | | | | | | | | | |
| | M Gengel | 2 | 6 | 2 | WC | M Gigante | 6$^3$ | 2 | | | | | | | | | |
| WC | M Gigante | 6 | 3 | 6 | | | | | | 1 | M Cressy | 6$^4$ | 6$^2$ | | | | |
| | B Lock | 3 | 1 | | | | | | | 6 | V Sachko | 7$^7$ | 7$^7$ | | | | |
| Q | Daniele Capecchi | 6 | 6 | | Q | D Capecchi | 7$^7$ | 1 | 2 | | | | | | | | |
| | A Erler | 6 | 2 | 2 | 6 | V Sachko | 6$^4$ | 6 | 6 | | | | | | | | |
| 6 | V Sachko | 3 | 6 | 6 | | | | | | | | | | 6 | V Sachko | 4 | 0$^r$ |
| 4 | Z Bergs | 5 | 7$^7$ | 5 | | | | | | | | | | | P Kotov | 6 | 4 |
| | P Kotov | 7 | 6$^5$ | 7 | | P Kotov | 7 | 6 | | | | | | | | | |
| Q | K Smith | 7 | 6 | | Q | K Smith | 5 | 2 | | | | | | | | | |
| Alt | V Vacherot | 5 | 4 | | | | | | | | P Kotov | 6 | 6 | | | | |
| | David Poljak | 7 | 4 | 3 | | | | | | 5 | M Bašić | 2 | 3 | | | | |
| | L Miedler | 5 | 6 | 6 | | L Miedler | 2 | 3 | | | | | | | | | |
| Q | S Danilov | 3 | 4 | | 5 | M Bašić | 6 | 6 | | | | | | | | | |
| 5 | M Bašić | 6 | 6 | | | | | | | | | | | | | | |

### 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 | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 8 | A Arnaboldi | 6 | 4 | | | | | | | | | | | | | | | |
| | R Brancaccio | 2 | 1$^r$ | | 8 | A Arnaboldi | 6 | 4 | 7 | | | | | | | | | |
| | G Brouwer | 6 | 6 | | | G Brouwer | 4 | 6 | 5 | | | | | | | | | |
| PR | J Lenz | 2 | 3 | | | | | | | 8 | A Arnaboldi | 6 | 6 | | | | | |
| | M Pervolarakis | 6 | 6 | | | | | | | | M Pervolarakis | 4 | 3 | | | | | |
| Q | Luca Potenza | 3 | 4 | | | M Pervolarakis | 6 | 6 | | | | | | | | | | |
| PR | F Baldi | 6 | 6 | | PR | F Baldi | 4 | 4 | | | | | | | | | | |
| 3 | S Caruso | 2 | 3 | | | | | | | | | | | 8 | A Arnaboldi | 4 | 6 | 6 |
| 7 | A Vavassori | 4 | 2 | | | | | | | | | | | WC | L Nardi | 6 | 3 | 4 |
| WC | L Nardi | 6 | 6 | | WC | L Nardi | 7$^8$ | 6 | | | | | | | | | | |
| | M Copil | 7$^7$ | 3 | 3 | | A Vatutin | 6$^6$ | 4 | | | | | | | | | | |
| | A Vatutin | 6$^4$ | 6 | 6 | | | | | | WC | L Nardi | 6 | 6 | | | | | |
| | M Viola | 7$^7$ | 4 | 7 | | | | | | | A Šetkić | 0 | 4 | | | | | |
| WC | L Rosol | 6$^1$ | 6 | 5 | | M Viola | 1 | 3 | | | | | | | | | | |
| | A Šetkić | 7 | 6 | | | A Šetkić | 6 | 6 | | | | | | | | | | |
| 2 | F Gaio | 5 | 2 | | | | | | | | | | | | | | | |