2019 International Challenger Zhangjiagang – Singles

Yasutaka Uchiyama was the defending champion but chose not to defend his title.

Marc Polmans won the title after defeating Lorenzo Giustino 6–4, 4–6, 7–6(7–4) in the final.

Seeds
All seeds receive a bye into the second round. • # 🇨🇦 Brayden Schnur (second round)

• # 🇦🇺 James Duckworth (third round)

• # 🇰🇷 Kwon Soon-woo (quarterfinals)

• # 🇯🇵 Hiroki Moriya (third round)

• # 🇯🇵 Yūichi Sugita (second round)

• # 🇮🇹 Lorenzo Giustino (final)

• # Blaž Rola (third round)

• # 🇨🇳 Zhang Ze (quarterfinals)

• # 🇯🇵 Go Soeda (second round)

• # 🇦🇺 Marc Polmans (champion)

• # Viktor Galović (semifinals, withdrew)

• # 🇪🇬 Mohamed Safwat (second round)

• # 🇮🇹 Stefano Napolitano (quarterfinals)

• # 🇨🇦 Filip Peliwo (third round)

• # 🇫🇷 Mathias Bourgue (semifinals)

• # 🇰🇷 Lee Duck-hee (withdrew)

• # 🇧🇾 Uladzimir Ignatik (quarterfinals)