[1][2] At the 2023 Argentina Open straight sets wins over Varvara Lepchenko[3] and Robin Montgomery[4] saw her reach her first WTA 125 quarterfinal, where ste lost to fifth seed and eventual champion Laura Pigossi.

[5] Seeded seventh, Sierra also made the last eight at the following week's 2023 Montevideo Open, defeating wildcard Carolina Bohrer Martins[6] and Ekaterine Gorgodze,[7] before her run was ended by top seed Diane Parry.

[8] Sierra reached her third WTA 125 quarterfinal at the 2024 Barranquilla Open, where she overcame Jang Su-jeong[9] and Liang En-shuo,[10] only to fall at the last eight stage once again, this time to Antonia Ružić.

159, Sierra made her Grand Slam tournament debut at the 2024 US Open after qualifying into the main draw.

[16] At the 2022 French Open, Sierra made her first junior Grand Slam final which she lost to Lucie Havlíčková, in straight sets.