# 2021 Las Vegas Challenger – Singles

Vasek Pospisil was the defending champion but chose not to defend his title.
J. J. Wolf won the title after defeating Stefan Kozlov 6–4, 6–4 in the final.

## Seeds

* Steve Johnson (first round)
* Denis Kudla (second round)
* Tennys Sandgren (first round, retired)
* Daniel Altmaier (second round)
* Taro Daniel (quarterfinals)
* Mitchell Krueger (first round)
* Emilio Gómez (quarterfinals)
* Jason Jung (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 | Final | Final | Final | Final |
| Alt | Stefan Kozlov | 6 | 6 | | | | |
| WC | Aleksandar Kovacevic | 2 | 4 | | | | |
| WC | Aleksandar Kovacevic | 2 | 4 | Alt | Stefan Kozlov | 4 | 4 |
| | | | | | J. J. Wolf | 6 | 6 |
| | Michael Mmoh | 3 | 2 | | J. J. Wolf | 6 | 6 |
| | J. J. Wolf | 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 | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | S Johnson | 4 | 4 | | | | | | | | | | | | | | |
| LL | A McHugh | 6 | 6 | | LL | A McHugh | 2 | 7 | 6$^{13}$ | | | | | | | | |
| Q | M Sasikumar | 2 | 4 | | Alt | S Kozlov | 6 | 5 | 7$^{15}$ | | | | | | | | |
| Alt | S Kozlov | 6 | 6 | | | | | | | Alt | S Kozlov | 7$^7$ | 6 | | | | |
| | J Kubler | 6$^5$ | 6 | 7$^8$ | | | | | | 7 | E Gómez | 6$^3$ | 4 | | | | |
| | Yo Watanuki | 7$^7$ | 0 | 6$^6$ | | J Kubler | 6 | 0 | 6$^8$ | | | | | | | | |
| | C-M Stebe | 6$^2$ | 0 | | 7 | E Gómez | 2 | 6 | 7$^{10}$ | | | | | | | | |
| 7 | E Gómez | 7$^7$ | 6 | | | | | | | | | | | Alt | S Kozlov | 6 | 6 |
| 4 | D Altmaier | 7$^8$ | 6 | | | | | | | | | | | WC | A Kovacevic | 2 | 4 |
| | Y Uchiyama | 6$^6$ | 1 | | 4 | D Altmaier | 6$^7$ | 3 | | | | | | | | | |
| WC | A Kovacevic | 6 | 3 | 7$^7$ | WC | A Kovacevic | 7$^9$ | 6 | | | | | | | | | |
| | C Eubanks | 1 | 6 | 6$^5$ | | | | | | WC | A Kovacevic | 6 | 6 | | | | |
| Q | D Young | 4 | 4 | | | | | | | 5 | T Daniel | 3 | 2 | | | | |
| | T Ito | 6 | 6 | | | T Ito | 2 | 1 | | | | | | | | | |
| WC | Jordan Sauer | 0 | 2 | | 5 | T Daniel | 6 | 6 | | | | | | | | | |
| 5 | T Daniel | 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 |
| 6 | M Krueger | 4 | 1 | | | | | | | | | | | | | |
| | A Vukic | 6 | 6 | | | A Vukic | 4 | 4 | | | | | | | | |
| | M Mmoh | 6 | 6 | | | M Mmoh | 6 | 6 | | | | | | | | |
| LL | N Chappell | 2 | 1 | | | | | | | M Mmoh | 6 | 6$^5$ | 6 | | | |
| Q | D Kelly | 6 | 6 | | | | | | | M Torpegaard | 1 | 7$^7$ | 1 | | | |
| WC | Christopher Bulus | 3 | 2 | | Q | D Kelly | 2 | 3 | | | | | | | | |
| | M Torpegaard | 6$^4$ | 7 | 3 | | M Torpegaard | 6 | 6 | | | | | | | | |
| 3 | T Sandgren | 7$^7$ | 5 | 0$^r$ | | | | | | | | | | M Mmoh | 3 | 2 |
| 8 | J Jung | 5 | 2 | | | | | | | | | | | J. J. Wolf | 6 | 6 |
| | T-S Kwiatkowski | 7 | 6 | | | T-S Kwiatkowski | 5 | 2 | | | | | | | | |
| | B Fratangelo | 7$^8$ | 6$^2$ | 6$^5$ | | E Escobedo | 7 | 6 | | | | | | | | |
| | E Escobedo | 6$^6$ | 7$^7$ | 7$^7$ | | | | | | E Escobedo | 3 | 3 | | | | |
| Q | S Mochizuki | 3 | 5 | | | | | | | J. J. Wolf | 6 | 6 | | | | |
| | J. J. Wolf | 6 | 7 | | | J. J. Wolf | 4 | 6 | 6 | | | | | | | |
| | B Schnur | 3 | 2 | | 2 | D Kudla | 6 | 3 | 0 | | | | | | | |
| 2 | D Kudla | 6 | 6 | | | | | | | | | | | | | |