# 2008 AIG Japan Open Tennis Championships – Men's singles

David Ferrer was the defending champion, but lost in the quarterfinals to Juan Martín del Potro.
Ninth-seeded Tomáš Berdych won in the final 6–1, 6–4, against Juan Martín del Potro.

## Seeds

All seeds received a bye into the second round.
* David Ferrer (quarterfinals)
* Andy Roddick (semifinals)
* Fernando González (quarterfinals)
* Richard Gasquet (semifinals)
* Juan Martín del Potro (final)
* Tommy Robredo (third round)
* Jo-Wilfried Tsonga (third round, retired due to an abdominal strain)
* Mikhail Youzhny (third round)
* Tomáš Berdych (champion)
* Gaël Monfils (withdrew due to a right shoulder injury)
* Jarkko Nieminen (third round)
* Rainer Schüttler (quarterfinals)
* Sam Querrey (second round)
* Jürgen Melzer (third round)
* Simone Bolelli (second round)
* Guillermo García López (second round)

## 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

| Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final |
| 1 | David Ferrer | 1 | 5 | | | | | | | | | |
| 5 | Juan Martín del Potro | 6 | 7 | | | | | | | | | |
| 5 | Juan Martín del Potro | 6 | 7 | 5 | Juan Martín del Potro | 6 | 4 | 7 | | | | |
| | | | | 4 | Richard Gasquet | 3 | 6 | 5 | | | | |
| 4 | Richard Gasquet | 6 | 6 | 4 | Richard Gasquet | 3 | 6 | 5 | | | | |
| 12 | Rainer Schüttler | 3 | 2 | | | | | | | | | |
| 12 | Rainer Schüttler | 3 | 2 | | | | | | 5 | Juan Martín del Potro | 1 | 4 |
| | | | | | | | | | 9 | Tomáš Berdych | 6 | 6 |
| 9 | Tomáš Berdych | 6 | 6 | | | | | | | | | | 9 | Tomáš Berdych | 6 | 6 |
| 3 | Fernando González | 0 | 4 | | | | | | | | | |
| 3 | Fernando González | 0 | 4 | 9 | Tomáš Berdych | 6$^3$ | 7 | 7$^7$ | | | | |
| | | | | 2 | Andy Roddick | 7$^7$ | 5 | 6$^3$ | | | | |
| | Viktor Troicki | 3 | 4 | 2 | Andy Roddick | 7$^7$ | 5 | 6$^3$ | | | | |
| 2 | Andy Roddick | 6 | 6 | | | | | | | | | |

### Top half
#### Section 1

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 1 | D Ferrer | 6 | 4 | 6 | | | | | | | | | |
| | J Levine | 4 | 6 | 6 | | J Levine | 4 | 6 | 1 | | | | | | | | | |
| Q | D Udomchoke | 6 | 1 | 0 | | | | | | 1 | D Ferrer | 4 | 6 | 6 | | | | |
| WC | Y Sugita | 3 | 6$^6$ | | | | | | | WC | T Suzuki | 6 | 3 | 2 | | | | |
| WC | T Suzuki | 6 | 7$^8$ | | WC | T Suzuki | 7$^7$ | 4 | 7$^7$ | | | | | | | | | |
| | | | | | 15 | S Bolelli | 6$^5$ | 6 | 6$^5$ | | | | | | | | | |
| | | | | | | | | | | | | | | | 1 | D Ferrer | 1 | 5 |
| | | | | | | | | | | | | | | | 5 | JM del Potro | 6 | 7 |
| | | | | | 11 | J Nieminen | 7$^9$ | 6 | | | | | | | | | | |
| Q | C Mamiit | 3 | 7 | 6 | Q | C Mamiit | 6$^7$ | 4 | | | | | | | | | | |
| LL | B Evans | 6 | 5 | 4 | | | | | | 11 | J Nieminen | 1 | 3 | | | | | |
| | D Sela | 7 | 6 | | | | | | | 5 | JM del Potro | 6 | 6 | | | | | |
| | B Phau | 5 | 1 | | | D Sela | 5 | 0 | | | | | | | | | | |
| | | | | | 5 | JM del Potro | 7 | 6 | | | | | | | | | | |

#### Section 2

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 4 | R Gasquet | 6 | 6 | | | | | | | | | | |
| Q | M Slanar | 4 | 6 | 6 | Q | M Slanar | 4 | 2 | | | | | | | | | | |
| | D Young | 6 | 3 | 2 | | | | | | 4 | R Gasquet | 6 | 6 | | | | | |
| | K Nishikori | 7$^7$ | 6$^5$ | 6 | | | | | | | K Nishikori | 1 | 2 | | | | | |
| | R Kendrick | 6$^3$ | 7$^7$ | 2 | | K Nishikori | 6 | 6 | | | | | | | | | | |
| | | | | | 16 | G García López | 4 | 4 | | | | | | | | | | |
| | | | | | | | | | | | | | | | 4 | R Gasquet | 6 | 6 |
| | | | | | | | | | | | | | | | 12 | R Schüttler | 3 | 2 |
| | | | | | 12 | R Schüttler | 6 | 6$^3$ | 6 | | | | | | | | | |
| WC | S Iwabuchi | 1 | 4 | | | H-t Lee | 3 | 7$^7$ | 3 | | | | | | | | | |
| | H-t Lee | 6 | 6 | | | | | | | 12 | R Schüttler | 6 | 6$^{12}$ | 6 | | | | |
| | F Cipolla | 7$^7$ | 7$^7$ | | | | | | | 8 | M Youzhny | 3 | 7$^{14}$ | 4 | | | | |
| | I Navarro | 6$^5$ | 6$^4$ | | | F Cipolla | 2 | 2 | | | | | | | | | | |
| | | | | | 8 | M Youzhny | 6 | 6 | | | | | | | | | | |

### Bottom half
#### Section 3

| First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | 6 | T Robredo | 6 | 6 | | | | | | | | | |
| | J Sirianni | 6 | 6 | | J Sirianni | 2 | 2 | | | | | | | | | |
| Q | Y Ito | 3 | 2 | | | | | | 6 | T Robredo | 6$^6$ | 2 | | | | |
| | R Karanušić | 6 | 6 | | | | | | 9 | T Berdych | 7$^8$ | 6 | | | | |
| Q | H Kondo | 2 | 2 | | R Karanušić | 3 | 4 | | | | | | | | | |
| | | | | 9 | T Berdych | 6 | 6 | | | | | | | | | |
| | | | | | | | | | | | | | 9 | T Berdych | 6 | 6 |
| | | | | | | | | | | | | | 3 | F González | 0 | 4 |
| | | | | 13 | S Querrey | 6$^5$ | 3 | | | | | | | | | |
| | G Soeda | 4 | 2 | | A Delić | 7$^7$ | 6 | | | | | | | | | |
| | A Delić | 6 | 6 | | | | | | | A Delić | 4 | 6$^4$ | | | | |
| | Y-h Lu | 6 | 7$^7$ | | | | | | 3 | F González | 6 | 7$^7$ | | | | |
| Q | L Gregorc | 4 | 6$^5$ | | Y-h Lu | 6 | 5 | 3 | | | | | | | | |
| | | | | 3 | F González | 1 | 7 | 6 | | | | | | | | |

#### Section 4

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Third round | Third round | Third round | Third round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals |
| | | | | | 7 | J-W Tsonga | 4 | 7$^7$ | 6 | | | | | | | | |
| | B Reynolds | 6 | 6 | | | B Reynolds | 6 | 6$^4$ | 4 | | | | | | | | |
| WC | T Ito | 3 | 1 | | | | | | | 7 | J-W Tsonga | 7 | 1$^r$ | | | | |
| | W Odesnik | 6 | 6 | | | | | | | | V Troicki | 5 | 2 | | | | |
| | K Kim | 4 | 3 | | | W Odesnik | 2 | 1 | | | | | | | | | |
| | | | | | | V Troicki | 6 | 6 | | | | | | | | | |
| | | | | | | | | | | | | | | | V Troicki | 3 | 4 |
| | | | | | | | | | | | | | | 2 | A Roddick | 6 | 6 |
| | | | | | 14 | J Melzer | 6 | 6 | | | | | | | | | |
| | S Stadler | 6 | 6 | | | S Stadler | 2 | 3 | | | | | | | | | |
| | P Petzschner | 2 | 4 | | | | | | | 14 | J Melzer | 6$^2$ | 2 | | | | |
| | I Minář | 7$^{11}$ | 2 | 6 | | | | | | 2 | A Roddick | 7$^7$ | 6 | | | | |
| | M Zverev | 6$^9$ | 6 | 2 | | I Minář | 6$^{11}$ | 7$^7$ | 6$^2$ | | | | | | | | |
| | | | | | 2 | A Roddick | 7$^{13}$ | 6$^4$ | 7$^7$ | | | | | | | | |