2021 Rancho Santa Fe Open – Singles

You Xiaodi was the defending champion but chose not to participate.

Rebecca Peterson won the title, defeating Elvina Kalieva in the final, 6–4, 6–0.

Seeds
• # 🇸🇪 Rebecca Peterson (champion)

• # 🇫🇷 Fiona Ferro (semifinals, retired)

• # 🇺🇸 Madison Brengle (semifinals)

• # 🇰🇿 Zarina Diyas (second round)

• # 🇯🇵 Misaki Doi (first round)

• # 🇸🇰 Kristína Kučová (quarterfinals)

• # 🇲🇽 Renata Zarazúa (first round)

• # Polona Hercog (quarterfinals)