2013 Western & Southern Open – Men's singles

Rafael Nadal defeated John Isner in the final, 7–6(10–8), 7–6(7–3) to win the men's singles tennis title at the 2013 Cincinnati Open. It was his record-extending 26th Masters title.

Roger Federer was the defending champion, but lost in the quarterfinals to Nadal.

Seeds
The top eight seeds receive a bye into the second round. • 🇷🇸 Novak Djokovic (quarterfinals)

• 🇬🇧 Andy Murray (quarterfinals)

• 🇪🇸 David Ferrer (third round)

• 🇪🇸 Rafael Nadal (champion)

• Roger Federer (quarterfinals)

• 🇨🇿 Tomáš Berdych (semifinals)

• 🇦🇷 Juan Martín del Potro (semifinals)

• 🇫🇷 Richard Gasquet (second round)

•  Stanislas Wawrinka (second round)

• 🇯🇵 Kei Nishikori (first round)

• 🇩🇪 Tommy Haas (third round)

• 🇨🇦 Milos Raonic (third round)

• 🇪🇸 Nicolás Almagro (first round)

• 🇮🇹 Fabio Fognini (first round)

• 🇫🇷 Gilles Simon (first round, retired)

• 🇵🇱 Jerzy Janowicz (first round)

Seeds
• # Ivan Dodig (first round, retired because of fatigue)

• # 🇦🇺 Bernard Tomic (first round)

• # 🇷🇺 Dmitry Tursunov (qualified)

• # 🇪🇸 Pablo Andújar (qualified)

• # Lu Yen-hsun (first round)

• # Grega Žemlja (qualifying competition)

• # 🇫🇷 Adrian Mannarino (qualified)

• # 🇵🇱 Łukasz Kubot (first round)

• # 🇫🇷 Édouard Roger-Vasselin (qualified)

• # 🇪🇸 Albert Ramos (first round)

• # 🇫🇷 Nicolas Mahut (first round)

• # 🇷🇺 Alex Bogomolov Jr. (first round)

• # 🇧🇪 David Goffin (qualified)

• # Ivo Karlović (qualifying competition)

Qualifiers
• # 🇩🇪 Benjamin Becker

• # 🇧🇪 David Goffin

• # 🇷🇺 Dmitry Tursunov

• # 🇪🇸 Pablo Andújar

• # 🇺🇸 Mackenzie McDonald

• # 🇫🇷 Édouard Roger-Vasselin

• # 🇫🇷 Adrian Mannarino