2013 PBZ Zagreb Indoors – Singles

Mikhail Youzhny was the defending champion but lost in the semifinals to top-seeded Marin Čilić. Čilić went on to win the title by defeating Jürgen Melzer 6–3, 6–1 in the final.

Seeds
• # Marin Čilić (champion)

• # 🇮🇹 Andreas Seppi (withdrew due to fever)

• # 🇷🇺 Mikhail Youzhny (semifinals)

• # 🇦🇹 Jürgen Melzer (final)

• # 🇸🇰 Martin Kližan (second round)

• # 🇨🇾 Marcos Baghdatis (second round)

• # 🇧🇬 Grigor Dimitrov (first round)

• # 🇸🇰 Lukáš Lacko (first round, retired due to lower back injury)

Seeds
• # 🇩🇪 Michael Berrer (qualified)

• # 🇩🇪 Philipp Petzschner (qualified)

• # 🇮🇹 Matteo Viola (qualifying competition, lucky loser)

• # 🇩🇪 Simon Greul (first round)

• # 🇬🇧 Jamie Baker (first round)

• # 🇹🇷 Marsel İlhan (first round)

• # 🇸🇰 Pavol Červenák (second round)

• # Boy Westerhof (second round)

Qualifiers
• # 🇩🇪 Michael Berrer

• # 🇩🇪 Philipp Petzschner

• # 🇷🇸 Ilija Bozoljac

• # Filip Veger

Lucky losers

 * 1)  Dino Marcan
 * 2) 🇮🇹 Matteo Viola