# 2021 Biella Challenger V – Singles

Daniel Masur was the defending champion but chose not to defend his title.
Juan Pablo Varillas won the title after defeating Guido Andreozzi 6–3, 6–1 in the final.

## Seeds

* Pedro Sousa (first round)
* Hugo Dellien (second round)
* Mackenzie McDonald (second round)
* Cedrik-Marcel Stebe (first round)
* Federico Gaio (quarterfinals)
* Hugo Gaston (first round)
* Juan Pablo Varillas (champion)
* Go Soeda (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 |
| 7 | Juan Pablo Varillas | 6 | 2 | 6 | | | | |
| | Alexandre Müller | 2 | 6 | 2 | | | | |
| | Alexandre Müller | 2 | 6 | 2 | 7 | Juan Pablo Varillas | 6 | 6 |
| | | | | | Q | Guido Andreozzi | 3 | 1 |
| Q | Guido Andreozzi | 7 | 6 | | Q | Guido Andreozzi | 3 | 1 |
| Alt | Andrea Collarini | 5 | 2 | | | | | |

### 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 | Semifinals |
| 1 | P Sousa | 6$^3$ | 4 | | | | | | | | | | | | | | | |
| | J Menezes | 7$^7$ | 6 | | | J Menezes | 7 | 2 | 6 | | | | | | | | | |
| WC | H Međedović | 7 | 7$^7$ | | WC | H Međedović | 5 | 6 | 4 | | | | | | | | | |
| | R Bemelmans | 5 | 6$^4$ | | | | | | | | J Menezes | 4 | 3 | | | | | |
| LL | D Kuzmanov | 6 | 1 | 6 | | | | | | 7 | JP Varillas | 6 | 6 | | | | | |
| | L Giustino | 3 | 6 | 3 | LL | D Kuzmanov | 1 | 7 | 6$^0$ | | | | | | | | | |
| | A Giannessi | 4 | 5 | | 7 | JP Varillas | 6 | 5 | 7$^7$ | | | | | | | | | |
| 7 | JP Varillas | 6 | 7 | | | | | | | | | | | 7 | JP Varillas | 6 | 2 | 6 |
| 3 | M McDonald | 3 | 6 | 6 | | | | | | | | | | | A Müller | 2 | 6 | 2 |
| | JM Cerúndolo | 6 | 4 | 3 | 3 | M McDonald | 7$^7$ | 2 | 4 | | | | | | | | | |
| WC | L Vanni | 6$^7$ | 0 | | | L Mayer | 6$^0$ | 6 | 6 | | | | | | | | | |
| | L Mayer | 7$^9$ | 6 | | | | | | | | L Mayer | 3 | 4 | | | | | |
| | Zh Zhang | 4 | 6 | 6 | | | | | | | A Müller | 6 | 6 | | | | | |
| Q | F Meligeni Alves | 6 | 4 | 4 | | Zh Zhang | 3 | 7$^7$ | 5 | | | | | | | | | |
| | A Müller | 1 | 6 | 6 | | A Müller | 6 | 6$^4$ | 7 | | | | | | | | | |
| 6 | H Gaston | 6 | 3 | 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 | G Soeda | 2 | 1 | | | | | | | | | | | | | | | |
| Q | M Marterer | 6 | 6 | | Q | M Marterer | 3 | 3 | | | | | | | | | | |
| Alt | J Clarke | 7 | 6 | | Alt | J Clarke | 6 | 6 | | | | | | | | | | |
| Q | V Galović | 5 | 2 | | | | | | | Alt | J Clarke | 6 | 3 | 5 | | | | |
| Q | G Andreozzi | 6 | 7 | | | | | | | Q | G Andreozzi | 3 | 6 | 7 | | | | |
| | K Coppejans | 2 | 5 | | Q | G Andreozzi | 3 | 6 | 6 | | | | | | | | | |
| LL | MT Barrios Vera | 6 | 6 | | LL | MT Barrios Vera | 6 | 3 | 3 | | | | | | | | | |
| 4 | C-M Stebe | 2 | 4 | | | | | | | | | | | | Q | G Andreozzi | 7 | 6 |
| 5 | F Gaio | 6$^3$ | 7$^7$ | 6 | | | | | | | | | | | Alt | A Collarini | 5 | 2 |
| | P Lorenzi | 7$^7$ | 6$^4$ | 2 | 5 | F Gaio | 6 | 6 | | | | | | | | | | |
| | F Horanský | 2 | 4 | | | J Domingues | 4 | 3 | | | | | | | | | | |
| | J Domingues | 6 | 6 | | | | | | | 5 | F Gaio | 6 | 4 | 1 | | | | |
| Alt | A Collarini | 6 | 6 | | | | | | | Alt | A Collarini | 4 | 6 | 6 | | | | |
| | A Bolt | 2 | 2 | | Alt | A Collarini | 6 | 7 | | | | | | | | | | |
| WC | S Napolitano | 0 | 7 | 1 | 2 | H Dellien | 1 | 5 | | | | | | | | | | |
| 2 | H Dellien | 6 | 5 | 6 | | | | | | | | | | | | | | |