# 2018 Rakuten Japan Open Tennis Championships – Singles

David Goffin was the defending champion, but withdrew before the competition began.
Daniil Medvedev won the title, defeating Kei Nishikori in the final, 6–2, 6–4.

## Seeds

* Marin Čilić (first round)
* Kevin Anderson (quarterfinals)
* Kei Nishikori (final)
* Diego Schwartzman (first round)
* Stefanos Tsitsipas (quarterfinals)
* Milos Raonic (quarterfinals)
* Chung Hyeon (first round)
* Richard Gasquet (semifinals)

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

### Finals

| Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final |
| | Denis Shapovalov | 3 | 3 | | | | |
| Q | Daniil Medvedev | 6 | 6 | | | | |
| Q | Daniil Medvedev | 6 | 6 | Q | Daniil Medvedev | 6 | 6 |
| | | | | 3 | Kei Nishikori | 2 | 4 |
| 3 | Kei Nishikori | 7$^7$ | 6 | 3 | Kei Nishikori | 2 | 4 |
| 8 | Richard Gasquet | 6$^2$ | 1 | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | M Čilić | 6 | 4 | 6$^1$ | | | | | | | | | | | | | | |
| | J-L Struff | 3 | 6 | 7$^7$ | | J-L Struff | 7$^7$ | 6$^2$ | 6 | | | | | | | | | |
| | J Chardy | 4 | 6 | 6 | | J Chardy | 6$^3$ | 7$^7$ | 4 | | | | | | | | | |
| | D Džumhur | 6 | 3 | 3 | | | | | | | J-L Struff | 6 | 6$^7$ | 4 | | | | |
| | S Wawrinka | 6 | 6 | | | | | | | | D Shapovalov | 4 | 7$^9$ | 6 | | | | |
| SE | T Fritz | 3 | 4 | | | S Wawrinka | 6 | 1 | 4 | | | | | | | | | |
| | D Shapovalov | 6 | 3 | 6 | | D Shapovalov | 4 | 6 | 6 | | | | | | | | | |
| 7 | H Chung | 3 | 6 | 2 | | | | | | | | | | | | D Shapovalov | 3 | 3 |
| 4 | D Schwartzman | 4 | 4 | | | | | | | | | | | | Q | D Medvedev | 6 | 6 |
| Q | D Medvedev | 6 | 6 | | Q | D Medvedev | 6 | 6 | | | | | | | | | | |
| Q | M Kližan | 6 | 7$^7$ | | Q | M Kližan | 4 | 3 | | | | | | | | | | |
| | S Johnson | 4 | 6$^4$ | | | | | | | Q | D Medvedev | 7$^7$ | 6 | | | | | |
| Q | Y Watanuki | 6$^7$ | 6 | 6 | | | | | | 6 | M Raonic | 6$^4$ | 3 | | | | | |
| | R Haase | 7$^9$ | 4 | 1 | Q | Y Watanuki | 3 | 6$^2$ | | | | | | | | | | |
| | A Mannarino | 3 | 4 | | 6 | M Raonic | 6 | 7$^7$ | | | | | | | | | | |
| 6 | M Raonic | 6 | 6 | | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 5 | S Tsitsipas | 6 | 6 | | | | | | | | | | | | | | |
| WC | T Daniel | 1 | 3 | | 5 | S Tsitsipas | 6 | 5 | 6 | | | | | | | | |
| | G Simon | 7$^7$ | 6$^5$ | 2 | | A de Minaur | 3 | 7 | 1 | | | | | | | | |
| | A de Minaur | 6$^1$ | 7$^7$ | 6 | | | | | | 5 | S Tsitsipas | 3 | 3 | | | | |
| | B Paire | 6 | 7$^7$ | | | | | | | 3 | K Nishikori | 6 | 6 | | | | |
| | N Jarry | 4 | 6$^1$ | | | B Paire | 3 | 5 | | | | | | | | | |
| WC | Y Sugita | 4 | 1 | | 3 | K Nishikori | 6 | 7 | | | | | | | | | |
| 3 | K Nishikori | 6 | 6 | | | | | | | | | | | 3 | K Nishikori | 7$^7$ | 6 |
| 8 | R Gasquet | 7$^{10}$ | 6 | | | | | | | | | | | 8 | R Gasquet | 6$^2$ | 1 |
| Q | D Kudla | 6$^8$ | 3 | | 8 | R Gasquet | 7$^7$ | 7$^7$ | | | | | | | | | |
| | N Kyrgios | 7 | 7$^7$ | | | N Kyrgios | 6$^4$ | 6$^1$ | | | | | | | | | |
| WC | Y Nishioka | 5 | 6$^3$ | | | | | | | 8 | R Gasquet | 7$^8$ | 7$^7$ | | | | |
| | M Marterer | 5 | 4 | | | | | | | 2 | K Anderson | 6$^6$ | 6$^4$ | | | | |
| | F Tiafoe | 7 | 6 | | | F Tiafoe | 3 | 6 | 2 | | | | | | | | |
| | M Ebden | 6 | 6$^1$ | 2 | 2 | K Anderson | 6 | 3 | 6 | | | | | | | | |
| 2 | K Anderson | 4 | 7$^7$ | 6 | | | | | | | | | | | | | |

## Qualifying
### Seeds

* Daniil Medvedev (qualified)
* Martin Kližan (qualified)
* Denis Kudla (qualified)
* Mackenzie McDonald (first round)
* Marius Copil (first round)
* Bradley Klahn (qualifying competition)
* Hubert Hurkacz (first round)
* Tim Smyczek (first round)

### Qualifiers

* Daniil Medvedev
* Martin Kližan
* Denis Kudla
* Yosuke Watanuki

### Qualifying draw
#### First qualifier

| First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 1 | Daniil Medvedev | 6 | 6 | | | | | |
| Alt | Hiroki Moriya | 3 | 3 | | | | | |
| Alt | Hiroki Moriya | 3 | 3 | 1 | Daniil Medvedev | 6$^4$ | 6 | 6 |
| | | | | PR | Egor Gerasimov | 7$^7$ | 3 | 3 |
| PR | Egor Gerasimov | 6 | 6 | PR | Egor Gerasimov | 7$^7$ | 3 | 3 |
| 5 | Marius Copil | 4 | 3 | | | | | |

#### Second qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 2 | Martin Kližan | 6 | 6 | | | | | |
| | Prajnesh Gunneswaran | 4 | 2 | | | | | |
| | Prajnesh Gunneswaran | 4 | 2 | | 2 | Martin Kližan | 6 | 6 |
| | | | | | 6 | Bradley Klahn | 3 | 4 |
| | Ruben Bemelmans | 6 | 3 | 6$^4$ | 6 | Bradley Klahn | 3 | 4 |
| 6 | Bradley Klahn | 2 | 6 | 7$^7$ | | | | |

#### Third qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 3 | Denis Kudla | 6 | 3 | 6 | | | | | |
| | Horacio Zeballos | 2 | 6 | 4 | | | | | |
| | Horacio Zeballos | 2 | 6 | 4 | 3 | Denis Kudla | 6 | 1 | 6 |
| | | | | | WC | Yasutaka Uchiyama | 3 | 6 | 3 |
| WC | Yasutaka Uchiyama | 6 | 6 | | WC | Yasutaka Uchiyama | 3 | 6 | 3 |
| 7 | Hubert Hurkacz | 2 | 2 | | | | | | |

#### Fourth qualifier

| First round | First round | First round | First round | First round | Qualifying competition | Qualifying competition | Qualifying competition | Qualifying competition |
| 4 | Mackenzie McDonald | 4 | 6 | 3 | | | | |
| WC | Tatsuma Ito | 6 | 1 | 6 | | | | |
| WC | Tatsuma Ito | 6 | 1 | 6 | WC | Tatsuma Ito | 2 | 4 |
| | | | | | WC | Yosuke Watanuki | 6 | 6 |
| WC | Yosuke Watanuki | 6 | 6 | | WC | Yosuke Watanuki | 6 | 6 |
| 8 | Tim Smyczek | 4 | 2 | | | | | |