2019 Knoxville Challenger – Singles

Reilly Opelka was the defending champion but chose not to defend his title.

Michael Mmoh won the title after defeating Christopher O'Connell 6–4, 6–4 in the final.

Seeds
All seeds receive a bye into the second round. • # 🇺🇸 Tommy Paul (semifinals)

• # 🇨🇦 Brayden Schnur (second round)

• # 🇺🇸 Bradley Klahn (second round)

• # 🇯🇵 Taro Daniel (second round)

• # 🇺🇸 Denis Kudla (second round)

• # 🇮🇹 Paolo Lorenzi (second round)

• # 🇺🇸 Marcos Giron (second round)

• # 🇦🇺 Christopher O'Connell (final)

• # Blaž Rola (quarterfinals)

• # 🇪🇨 Emilio Gómez (third round)

• # 🇨🇦 Peter Polansky (third round)

• # Darian King (second round)

• # 🇨🇦 Vasek Pospisil (third round, retired)

• # 🇫🇷 Maxime Janvier (withdrew)

• # 🇷🇺 Alexey Vatutin (second round)

• # 🇺🇸 Mitchell Krueger (second round)