2021 JSM Challenger of Champaign–Urbana – Singles

J. J. Wolf was the defending champion but lost in the semifinals to Stefan Kozlov.

Kozlov won the title after defeating Aleksandar Vukic 5–7, 6–3, 6–4 in the final.

Seeds
• # 🇩🇪 Daniel Altmaier (second round)

• # 🇺🇸 Mitchell Krueger (quarterfinals)

• # 🇺🇸 J. J. Wolf (semifinals)

• # 🇦🇺 Aleksandar Vukic (final)

• # Jason Jung (second round)

• # 🇮🇳 Prajnesh Gunneswaran (first round)

• # Blaž Rola (first round)

• # 🇺🇸 Stefan Kozlov (champion)