# 2021 Korea Open – Singles

Karolína Muchová was the reigning champion, but chose not to participate.
Zhu Lin won her first WTA 125 tournament, defeating Kristina Mladenovic in the final, 6–0, 6–4.

## Seeds

* Kristina Mladenovic (final)
* Zhu Lin (champion)
* Réka Luca Jani (second round)
* Valentini Grammatikopoulou (second round)
* Arianne Hartono (quarterfinals)
* Jang Su-jeong (second round)
* Isabella Shinikova (quarterfinals)
* Yuki Naito (quarterfinals)

## 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 |
| 1 | Kristina Mladenovic | 3 | 7 | 7$^7$ | | | | |
| | Ekaterina Kazionova | 6 | 5 | 6$^4$ | | | | |
| | Ekaterina Kazionova | 6 | 5 | 6$^4$ | 1 | Kristina Mladenovic | 0 | 4 |
| | | | | | 2 | Zhu Lin | 6 | 6 |
| | Anastasia Kulikova | 1 | 6$^6$ | | 2 | Zhu Lin | 6 | 6 |
| 2 | Zhu Lin | 6 | 7$^8$ | | | | | |

### 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 | Semifinals |
| | | | | | 1 | K Mladenovic | 6 | 5 | 6 | | | | | | | | | | |
| | J-y Seo | 1 | 1 | | | N-l Han | 4 | 7 | 0 | | | | | | | | | | |
| | N-l Han | 6 | 6 | | | | | | | 1 | K Mladenovic | 5 | 6 | 6 | | | | | |
| Alt | J Moon | 0 | 1 | | | | | | | 8 | Y Naito | 7 | 2 | 4 | | | | | |
| WC | B Fruhvirtová | 6 | 6 | | WC | B Fruhvirtová | 4 | 2 | | | | | | | | | | | |
| WC | E-y Park | 1 | 4 | | 8 | Y Naito | 6 | 6 | | | | | | | | | | | |
| 8 | Y Naito | 6 | 6 | | | | | | | | | | | | 1 | K Mladenovic | 3 | 7 | 7$^7$ |
| | | | | | | | | | | | | | | | | E Kazionova | 6 | 5 | 6$^4$ |
| | | | | | 3 | RL Jani | 5 | 2 | | | | | | | | | | | |
| | D-b Kim | 2 | 3 | | | E Kazionova | 7 | 6 | | | | | | | | | | | |
| | E Kazionova | 6 | 6 | | | | | | | | E Kazionova | 6 | 5 | 7$^7$ | | | | | |
| | F Contreras | 3 | 1 | | | | | | | | L Fruhvirtová | 3 | 7 | 6$^4$ | | | | | |
| | L Fruhvirtová | 6 | 6 | | | L Fruhvirtová | 7 | 6 | | | | | | | | | | | |
| WC | D-y Back | 6 | 3 | 3 | 6 | S-j Jang | 5 | 3 | | | | | | | | | | | |
| 6 | S-j Jang | 3 | 6 | 6 | | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 5 | A Hartono | 6 | 6 | | | | | | | | | | | | | |
| | C Zhao | 2 | 3 | | 5 | A Hartono | 6 | 6 | | | | | | | | |
| | O-y Choi | 3 | 6 | 6$^4$ | | J-h Choi | 1 | 1 | | | | | | | | |
| | J-h Choi | 6 | 4 | 7$^7$ | | | | | 5 | A Hartono | 2 | 4 | | | | |
| | A Kulikova | 6 | 6 | | | | | | | A Kulikova | 6 | 6 | | | | |
| | R Bhatia | 0 | 2 | | | A Kulikova | 6 | 6 | | | | | | | | |
| | | | | | 4 | V Grammatikopoulou | 1 | 2 | | | | | | | | |
| | | | | | | | | | | | | | | A Kulikova | 1 | 6$^6$ |
| 7 | I Shinikova | 6 | 6 | | | | | | | | | | 2 | L Zhu | 6 | 7$^8$ |
| | Y-w Jeong | 4 | 1 | | 7 | I Shinikova | 6 | 6 | | | | | | | | |
| | O Tjandramulia | 3 | 2 | | WC | B-y Jeong | 1 | 0 | | | | | | | | |
| WC | B-y Jeong | 6 | 6 | | | | | | 7 | I Shinikova | 3 | 0 | | | | |
| | P Plipuech | 1 | 6 | 6 | | | | | 2 | L Zhu | 6 | 6 | | | | |
| | E-h Lee | 6 | 3 | 4 | | P Plipuech | 1 | 1 | | | | | | | | |
| | | | | | 2 | L Zhu | 6 | 6 | | | | | | | | |