# 2021 US Open – Girls' singles

Camila Osorio was the defending champion, having won the previous edition in 2019, but was no longer eligible to participate in junior events. She participated in the women's singles event, but lost to Ons Jabeur in the second round.
Robin Montgomery won the title, defeating Kristina Dmitruk in the final, 6–2, 6–4.

## Seeds

All seeds received a bye into the second round.
    01. Victoria Jiménez Kasintseva (quarterfinals)
    02. Alex Eala (quarterfinals)
    03. Diana Shnaider (second round)
    04. Ane Mintegi del Olmo (second round)
    05. Linda Fruhvirtová (third round)
    06. Kristina Dmitruk (final)
    07. Robin Montgomery (champion)
    08. Océane Babel (second round)
    09. Natália Szabanin (third round)
    10. Madison Sieg (second round)
    11. Mara Guth (second round)
    12. Elvina Kalieva (quarterfinals)
    13. Matilda Mutavdzic (third round)
    14. Dana Guzmán (second round, retired)
    15. Michaela Laki (third round)
    16. Ashlyn Krueger (second round)
Click on the seed number of a player to go to their draw section.

## 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

| Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final |
| 1 | Victoria Jiménez Kasintseva | 3 | 2 | | | | | | | | | | |
| 7 | Robin Montgomery | 6 | 6 | | | | | | | | | | |
| 7 | Robin Montgomery | 6 | 6 | | 7 | Robin Montgomery | 2 | 6 | 6 | | | | |
| | | | | | | Solana Sierra | 6 | 3 | 4 | | | | |
| | Solana Sierra | 4 | 6 | 7$^7$ | | Solana Sierra | 6 | 3 | 4 | | | | |
| 12 | Elvina Kalieva | 6 | 3 | 6$^5$ | | | | | | | | | |
| 12 | Elvina Kalieva | 6 | 3 | 6$^5$ | | | | | | 7 | Robin Montgomery | 6 | 6 |
| | | | | | | | | | | 6 | Kristina Dmitruk | 2 | 4 |
| 6 | Kristina Dmitruk | 6 | 3 | 6 | | | | | | | | | | 6 | Kristina Dmitruk | 2 | 4 |
| | Petra Marčinko | 3 | 6 | 3 | | | | | | | | | |
| | Petra Marčinko | 3 | 6 | 3 | 6 | Kristina Dmitruk | 6 | 6 | | | | | |
| | | | | | | Sebastianna Scilipoti | 1 | 2 | | | | | |
| | Sebastianna Scilipoti | 7 | 6 | | | Sebastianna Scilipoti | 1 | 2 | | | | | |
| 2 | Alex Eala | 5 | 3 | | | | | | | | | | |

### Top half
#### Section 1

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 1 | V Jiménez Kasintseva | 6 | 6 | | | | | | | | | |
| Q | Theadora Rabman | 7 | 6 | | Q | T Rabman | 1 | 0 | | | | | | | | | |
| | Laura Hietaranta | 5 | 2 | | | | | | 1 | V Jiménez Kasintseva | 6$^5$ | 6 | 6 | | | | |
| WC | Liv Hovde | 2 | 6 | 2 | | | | | | J Kolodynska | 7$^7$ | 3 | 4 | | | | |
| | Jana Kolodynska | 6 | 1 | 6 | | J Kolodynska | 6 | 0 | | | | | | | | | |
| | | | | | 14 | D Guzmán | 2 | 0$^r$ | | | | | | | | | |
| | | | | | | | | | | | | | | 1 | V Jiménez Kasintseva | 3 | 2 |
| | | | | | | | | | | | | | | 7 | R Montgomery | 6 | 6 |
| | | | | | 9 | N Szabanin | 6 | 7$^7$ | | | | | | | | | |
| | Alina Shcherbinina | 6$^7$ | 6 | 6 | | A Shcherbinina | 4 | 6$^5$ | | | | | | | | | |
| WC | Amelia Honer | 7$^9$ | 4 | 4 | | | | | 9 | N Szabanin | 2 | 7 | 4 | | | | |
| Q | Annabelle Xu | 6 | 6 | | | | | | 7 | R Montgomery | 6 | 5 | 6 | | | | |
| | Hanne Vandewinkel | 0 | 3 | | Q | A Xu | 2 | 0 | | | | | | | | | |
| | | | | | 7 | R Montgomery | 6 | 6 | | | | | | | | | |

#### Section 2

| First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | 4 | A Mintegi del Olmo | 6 | 5 | 3 | | | | | | | | | | |
| WC | Sarah Hamner | 3 | 1 | | S Sierra | 4 | 7 | 6 | | | | | | | | | | |
| | Solana Sierra | 6 | 6 | | | | | | | S Sierra | 3 | 6 | 7$^7$ | | | | | |
| WC | Tatum Evans | 2 | 1 | | | | | | 13 | M Mutavdzic | 6 | 4 | 6$^4$ | | | | | |
| Q | Lucija Ćirić Bagarić | 6 | 6 | Q | L Ćirić Bagarić | 3 | 1 | | | | | | | | | | | |
| | | | | 13 | M Mutavdzic | 6 | 6 | | | | | | | | | | | |
| | | | | | | | | | | | | | | | S Sierra | 4 | 6 | 7$^7$ |
| | | | | | | | | | | | | | | 12 | E Kalieva | 6 | 3 | 6$^5$ |
| | | | | 12 | E Kalieva | 6 | 6 | | | | | | | | | | | |
| | Radka Zelníčková | 3 | 1 | | R Brantmeier | 3 | 3 | | | | | | | | | | | |
| | Reese Brantmeier | 6 | 6 | | | | | | 12 | E Kalieva | 7$^7$ | 6 | | | | | | |
| | Clervie Ngounoue | 6 | 6 | | | | | | 5 | L Fruhvirtová | 6$^3$ | 4 | | | | | | |
| | Julia Middendorf | 3 | 3 | | C Ngounoue | 0 | 2 | | | | | | | | | | | |
| | | | | 5 | L Fruhvirtová | 6 | 6 | | | | | | | | | | | |

### Bottom half
#### Section 3

| First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | 6 | K Dmitruk | 6 | 6$^5$ | 6 | | | | | | | | | |
| | Johanne Svendsen | 7 | 6 | | J Svendsen | 3 | 7$^7$ | 2 | | | | | | | | | |
| Q | Valencia Xu | 5 | 2 | | | | | | 6 | K Dmitruk | 6 | 6 | | | | | |
| | Linda Klimovičová | 5 | 1 | | | | | | LL | K Wiersholm | 4 | 1 | | | | | |
| LL | Katja Wiersholm | 7 | 6 | LL | K Wiersholm | 5 | 6 | 6 | | | | | | | | | |
| | | | | 11 | M Guth | 7 | 4 | 1 | | | | | | | | | |
| | | | | | | | | | | | | | 6 | K Dmitruk | 6 | 3 | 6 |
| | | | | | | | | | | | | | | P Marčinko | 3 | 6 | 3 |
| | | | | 16 | A Krueger | 6 | 4 | 3 | | | | | | | | | |
| Q | Yang Ya-yi | 4 | 6$^7$ | | P Marčinko | 3 | 6 | 6 | | | | | | | | | |
| | Petra Marčinko | 6 | 7$^9$ | | | | | | | P Marčinko | 7 | 6 | | | | | |
| | Alexis Blokhina | 7$^8$ | 6 | | | | | | | A Blokhina | 5 | 1 | | | | | |
| | Julia García | 6$^6$ | 0 | | A Blokhina | 6 | 7$^7$ | | | | | | | | | | |
| | | | | 3 | D Shnaider | 2 | 6$^5$ | | | | | | | | | | |

#### Section 4

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 8 | O Babel | 4 | 7$^7$ | 3 | | | | | | | | | |
| | Sebastianna Scilipoti | 6 | 1 | 6 | | S Scilipoti | 6 | 6$^0$ | 6 | | | | | | | | | |
| WC | Eleana Yu | 3 | 6 | 4 | | | | | | | S Scilipoti | 7$^8$ | 7$^7$ | | | | | |
| | Sofia Costoulas | 5 | | | | | | | | | S Costoulas | 6$^6$ | 6$^5$ | | | | | |
| | Sabina Zeynalova | 4$^r$ | | | | S Costoulas | 6 | 3 | 6 | | | | | | | | | |
| | | | | | 10 | M Sieg | 3 | 6 | 3 | | | | | | | | | |
| | | | | | | | | | | | | | | | | S Scilipoti | 7 | 6 |
| | | | | | | | | | | | | | | | 2 | A Eala | 5 | 3 |
| | | | | | 15 | M Laki | 6 | 6 | | | | | | | | | | |
| | Bianca Behúlová | 2 | 6 | 3 | | E Coleman | 0 | 4 | | | | | | | | | | |
| | Elizabeth Coleman | 6 | 2 | 6 | | | | | | 15 | M Laki | 6 | 5 | 4 | | | | |
| Q | Pimrada Jattavapornvanit | 1 | 6$^3$ | | | | | | | 2 | A Eala | 4 | 7 | 6 | | | | |
| WC | Charlotte Owensby | 6 | 7$^7$ | | WC | C Owensby | 3 | 3 | | | | | | | | | | |
| | | | | | 2 | A Eala | 6 | 6 | | | | | | | | | | |

## Qualifying
### Seeds

* Brenda Fruhvirtová (first round)
* Mirra Andreeva (qualifying competition)
* Lucija Ćirić Bagarić (qualified)
* Valencia Xu (qualified)
* Annabelle Xu (qualified)
* Victoria Mboko (first round)
* Pimrada Jattavapornvanit (qualified)
* Chelsea Fontenel (first round)
* Erika Matsuda (first round)
* Yang Ya-yi (qualified)
* Alejandra Cruz (qualifying competition)
* Marina Stakusic (qualifying competition)

### Qualifiers

* Yang Ya-yi
* Pimrada Jattavapornvanit
* Lucija Ćirić Bagarić
* Valencia Xu
* Annabelle Xu
* Theadora Rabman

### Lucky loser

* Katja Wiersholm

### Draw
#### First qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 1 | Brenda Fruhvirtová | 2 | 4 | | | | | |
| WC | Ariana Pursoo | 6 | 6 | | | | | |
| WC | Ariana Pursoo | 6 | 6 | WC | Ariana Pursoo | 7$^7$ | 2 | [11] |
| | | | | 10 | Yang Ya-yi | 6$^4$ | 6 | [13] |
| | Clarine Lerby | 3 | 4 | 10 | Yang Ya-yi | 6$^4$ | 6 | [13] |
| 10 | Yang Ya-yi | 6 | 6 | | | | | |

#### Second qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 2 | Mirra Andreeva | 6 | 6 | | | | |
| | Qavia Lopez | 0 | 1 | | | | |
| | Qavia Lopez | 0 | 1 | 2 | Mirra Andreeva | 4 | 5 |
| | | | | 7 | Pimrada Jattavapornvanit | 6 | 7 |
| | Fatima Ingrid Amartha Keita | 4 | 0 | 7 | Pimrada Jattavapornvanit | 6 | 7 |
| 7 | Pimrada Jattavapornvanit | 6 | 6 | | | | |

#### Third qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 3 | Lucija Ćirić Bagarić | 6 | 6 | | | | | |
| | Inès Bekrar | 0 | 1 | | | | | |
| | Inès Bekrar | 0 | 1 | 3 | Lucija Ćirić Bagarić | 6 | 3 | [10] |
| | | | | 12 | Marina Stakusic | 2 | 6 | [7] |
| | Alexia Harmon | 1 | 2 | 12 | Marina Stakusic | 2 | 6 | [7] |
| 12 | Marina Stakusic | 6 | 6 | | | | | |

#### Fourth qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 4 | Valencia Xu | 6 | 6 | | | | | |
| | Tatyana Nikolenko | 3 | 4 | | | | | |
| | Tatyana Nikolenko | 3 | 4 | | 4 | Valencia Xu | 6 | 7$^7$ |
| | | | | | | Mia Kupres | 3 | 6$^1$ |
| | Mia Kupres | 4 | 6 | [11] | | Mia Kupres | 3 | 6$^1$ |
| 9 | Erika Matsuda | 6 | 3 | [9] | | | | |

#### Fifth qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 5 | Annabelle Xu | 6 | 6 | | | | |
| | Kylie Bilchev | 4 | 2 | | | | |
| | Kylie Bilchev | 4 | 2 | 5 | Annabelle Xu | 6 | 6 |
| | | | | WC | Katja Wiersholm | 3 | 3 |
| WC | Katja Wiersholm | 6 | 6 | WC | Katja Wiersholm | 3 | 3 |
| 8 | Chelsea Fontenel | 2 | 4 | | | | |

#### Sixth qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 6 | Victoria Mboko | 3 | 6 | [4] | | | | | |
| WC | Theadora Rabman | 6 | 2 | [10] | | | | | |
| WC | Theadora Rabman | 6 | 2 | [10] | WC | Theadora Rabman | 6 | 6$^4$ | [10] |
| | | | | | 11 | Alejandra Cruz | 1 | 7$^7$ | [1] |
| WC | Yuina Igarashi | 1 | 2 | | 11 | Alejandra Cruz | 1 | 7$^7$ | [1] |
| 11 | Alejandra Cruz | 6 | 6 | | | | | | |