2018 Rakuten Japan Open Tennis Championships

The 2018 Rakuten Japan Open Tennis Championships was a men's tennis tournament played on indoor hard courts. It was the 45th edition of the Japan Open, and part of the 500 Series of the 2018 ATP World Tour. It was held at the Musashino Forest Sport Plaza in Tokyo, Japan, from October 1 through October 7, 2018. Unseeded Daniil Medvedev, who entered the main draw as a qualifier, won the singles title.

Seeds

 * 1 Rankings are as of September 24, 2018.

Other entrants
The following players received wildcards into the singles main draw:
 * 🇯🇵 Taro Daniel
 * 🇯🇵 Yoshihito Nishioka
 * 🇯🇵 Yūichi Sugita

The following player received entry as a special exempt:
 * 🇺🇸 Taylor Fritz

The following players received entry from the qualifying draw:
 * 🇸🇰 Martin Kližan
 * 🇺🇸 Denis Kudla
 * 🇷🇺 Daniil Medvedev
 * 🇯🇵 Yosuke Watanuki

Withdrawals

 * Before the tournament
 * 🇧🇪 David Goffin → replaced by 🇦🇺 Matthew Ebden
 * 🇫🇷 Lucas Pouille → replaced by 🇩🇪 Jan-Lennard Struff

Seeds

 * Rankings are as of September 24, 2018.

Other entrants
The following pairs received wildcards into the doubles main draw:
 * 🇯🇵 Yoshihito Nishioka / 🇯🇵 Kaito Uesugi
 * 🇬🇧 Joe Salisbury / 🇯🇵 Yasutaka Uchiyama

The following pair received entry from the qualifying draw:
 * 🇫🇷 Fabrice Martin / 🇫🇷 Gilles Simon

Singles

 * 🇷🇺 Daniil Medvedev defeated 🇯🇵 Kei Nishikori 6–2, 6–4

Doubles

 * 🇯🇵 Ben McLachlan / 🇩🇪 Jan-Lennard Struff defeated Raven Klaasen / 🇳🇿 Michael Venus 6–4, 7–5