2009 Heineken Open – Singles

Philipp Kohlschreiber was the defending champion, but withdrew in the quarterfinals due to a shoulder injury.

In the final, Juan Martín del Potro defeated Sam Querrey, 6–4, 6–4.

Seeds
• # 🇦🇷 Juan Martín del Potro (champion)

• # 🇪🇸 David Ferrer (semifinals)

• # 🇸🇪 Robin Söderling (semifinals)

• # 🇪🇸 Nicolás Almagro (quarterfinals)

• # 🇩🇪 Philipp Kohlschreiber (quarterfinals, withdrew due to a shoulder injury)

• # 🇺🇸 Sam Querrey (final)

• # 🇪🇸 Albert Montañés (first round)

• # 🇦🇷 Juan Mónaco (second round)

Seeds
• # 🇮🇹 Philipp Petzschner (withdrew, due to illness)

• # 🇪🇸 Óscar Hernández (qualified)

• # 🇺🇸 Bobby Reynolds (qualified)

• # 🇪🇸 Iván Navarro (second round)

• # Nicolás Massú (first round)

• # 🇦🇷 Diego Junqueira (second round)

• # 🇺🇸 Vince Spadea (second round)

• # 🇧🇷 Thomaz Bellucci (qualifying competition)

Qualifiers
• # 🇱🇺 Gilles Müller

• # 🇪🇸 Óscar Hernández

• # 🇺🇸 Bobby Reynolds

• # 🇺🇸 John Isner