# 2021 Nur-Sultan Challenger – Singles

There was no defending champion as the last edition of the tournament was canceled due to the COVID-19 pandemic.
Mackenzie McDonald won the title after defeating Jurij Rodionov 6–1, 6–2 in the final.

## Seeds

* Mikhail Kukushkin (first round)
* Evgeny Donskoy (first round)
* Cedrik-Marcel Stebe (withdrew)
* Prajnesh Gunneswaran (semifinals)
* Henri Laaksonen (semifinals)
* Jurij Rodionov (final)
* Martin Kližan (quarterfinals)
* Blaž Rola (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 |
| | Mackenzie McDonald | 6 | 6 | | | | | |
| 5 | Henri Laaksonen | 2 | 1 | | | | | |
| 5 | Henri Laaksonen | 2 | 1 | | | Mackenzie McDonald | 6 | 6 |
| | | | | | 6 | Jurij Rodionov | 1 | 2 |
| 4 | Prajnesh Gunneswaran | 2 | 6 | 3 | 6 | Jurij Rodionov | 1 | 2 |
| 6 | Jurij Rodionov | 6 | 3 | 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 | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | M Kukushkin | 5 | 5 | | | | | | | | | | | | | | | |
| | M McDonald | 7 | 7 | | | M McDonald | 6 | 6 | | | | | | | | | | |
| | D Istomin | 6$^6$ | 6 | 6 | | D Istomin | 2 | 3 | | | | | | | | | | |
| WC | D Yevseyev | 7$^8$ | 3 | 3 | | | | | | | M McDonald | 6 | 3 | 7$^7$ | | | | |
| | F Ferreira Silva | 6 | 6 | | | | | | | | F Ferreira Silva | 4 | 6 | 6$^3$ | | | | |
| | S Ofner | 3 | 4 | | | F Ferreira Silva | 6 | 3 | 6 | | | | | | | | | |
| Q | P Kotov | 6 | 7$^9$ | | Q | P Kotov | 1 | 6 | 4 | | | | | | | | | |
| 8 | B Rola | 4 | 6$^7$ | | | | | | | | | | | | | M McDonald | 6 | 6 |
| Q | B Bobrov | 2 | 1 | | | | | | | | | | | | 5 | H Laaksonen | 2 | 1 |
| | K Żuk | 6 | 6 | | | K Żuk | 6 | 4 | | | | | | | | | | |
| Alt | T-l Wu | 6 | 7 | | Alt | T-l Wu | 3 | 2$^r$ | | | | | | | | | | |
| | H Grenier | 4 | 5 | | | | | | | | K Żuk | 4 | 3 | | | | | |
| Q | R Peniston | 3 | 6 | 4 | | | | | | 5 | H Laaksonen | 6 | 6 | | | | | |
| | B Gojo | 6 | 1 | 6 | | B Gojo | 6 | 5 | 2 | | | | | | | | | |
| LL | R Quiroz | 4 | 2 | | 5 | H Laaksonen | 1 | 7 | 6 | | | | | | | | | |
| 5 | H Laaksonen | 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 | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 7 | M Kližan | 6 | 4 | 7$^7$ | | | | | | | | | | | | | | | |
| WC | T Skatov | 4 | 6 | 6$^5$ | 7 | M Kližan | 6$^7$ | 6 | 7$^7$ | | | | | | | | | | |
| | D Popko | 4 | 6 | 6$^7$ | Alt | U Blanch | 7$^9$ | 2 | 6$^5$ | | | | | | | | | | |
| Alt | U Blanch | 6 | 2 | 7$^9$ | | | | | | 7 | M Kližan | 3 | 6 | 4 | | | | | |
| | A Müller | 6$^8$ | 6 | 1 | | | | | | 4 | P Gunneswaran | 6 | 4 | 6 | | | | | |
| | B Schnur | 7$^{10}$ | 3 | 6 | | B Schnur | 6 | 3 | 0 | | | | | | | | | | |
| WC | Dostanbek Tashbulatov | 2 | 3 | | 4 | P Gunneswaran | 3 | 6 | 6 | | | | | | | | | | |
| 4 | P Gunneswaran | 6 | 6 | | | | | | | | | | | | 4 | P Gunneswaran | 2 | 6 | 3 |
| 6 | J Rodionov | 6 | 6 | | | | | | | | | | | | 6 | J Rodionov | 6 | 3 | 6 |
| LL | I Nedelko | 3 | 3 | | 6 | J Rodionov | 6 | 6 | | | | | | | | | | | |
| | T Ito | 6 | 6 | | | T Ito | 3 | 2 | | | | | | | | | | | |
| Q | V Manafov | 4 | 4 | | | | | | | 6 | J Rodionov | 6 | 6 | | | | | | |
| | P Polansky | 3 | 4 | | | | | | | | T Macháč | 2 | 3 | | | | | | |
| | M Marterer | 6 | 6 | | | M Marterer | 4 | 6 | 3 | | | | | | | | | | |
| | T Macháč | 6 | 3 | 6 | | T Macháč | 6 | 3 | 6 | | | | | | | | | | |
| 2 | E Donskoy | 3 | 6 | 1 | | | | | | | | | | | | | | | |