# 2004 Brasil Open – Singles

Sjeng Schalken was the defending champion but did not compete that year.
Gustavo Kuerten won in the final 3–6, 6–2, 6–3 against Agustín Calleri.

## Seeds

* Carlos Moyá (first round)
* Nicolás Massú (first round)
* Gustavo Kuerten (champion)
* Agustín Calleri (final)
* Mariano Zabaleta (first round)
* Félix Mantilla (first round)
* Gastón Gaudio (second round)
* Juan Ignacio Chela (quarterfinals)

## 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 | Semifinals | Final | Final | Final | Final | Final |
| | José Acasuso | 4 | 3 | | | | | | |
| 3 | Gustavo Kuerten | 6 | 6 | | | | | | |
| 3 | Gustavo Kuerten | 6 | 6 | | 3 | Gustavo Kuerten | 3 | 6 | 6 |
| | | | | | 4 | Agustín Calleri | 6 | 2 | 3 |
| 4 | Agustín Calleri | 6 | 5 | 6 | 4 | Agustín Calleri | 6 | 2 | 3 |
| | Luis Horna | 4 | 7 | 1 | | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | C Moyá | 3 | 3 | | | | | | | | | | | | | | |
| | T Behrend | 6 | 6 | | | T Behrend | 6 | 6 | | | | | | | | | |
| | H Levy | 4 | 6$^3$ | | | R Ramírez Hidalgo | 2 | 2 | | | | | | | | | |
| | R Ramírez Hidalgo | 6 | 7$^7$ | | | | | | | T Behrend | 6 | 2 | 4 | | | | |
| | C Rochus | 3 | 4 | | | | | | | J Acasuso | 0 | 6 | 6 | | | | |
| | J Acasuso | 6 | 6 | | | J Acasuso | 7$^7$ | 6 | | | | | | | | | |
| | F Volandri | 6 | 6 | | | F Volandri | 6$^4$ | 2 | | | | | | | | | |
| 6 | F Mantilla | 2 | 2 | | | | | | | | | | | | J Acasuso | 4 | 3 |
| 3 | G Kuerten | 3 | 6 | 6 | | | | | | | | | | 3 | G Kuerten | 6 | 6 |
| | Ó Hernández | 6 | 2 | 3 | 3 | G Kuerten | 7$^7$ | 6 | | | | | | | | | |
| | R Gasquet | 6 | 7$^7$ | | | R Gasquet | 6$^3$ | 3 | | | | | | | | | |
| WC | F Ferreiro | 0 | 6$^5$ | | | | | | 3 | G Kuerten | 3 | 7 | 7 | | | | |
| Q | F Squillari | 6 | 7 | | | | | | Q | F Squillari | 6 | 5 | 5 | | | | |
| Q | J-R Lisnard | 2 | 5 | | Q | F Squillari | 7$^7$ | 6 | | | | | | | | | |
| WC | R Mello | 2 | 4 | | 7 | G Gaudio | 6$^3$ | 3 | | | | | | | | | |
| 7 | G Gaudio | 6 | 6 | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 8 | J I Chela | 6 | 6 | | | | | | | | | | | | | | |
| | F Saretta | 2 | 2 | 8 | J I Chela | 6 | 6 | | | | | | | | | | |
| | D Ferrer | 6 | 5 | | D Ferrer | 2 | 4 | | | | | | | | | | |
| | N Lapentti | 4 | 2$^r$ | | | | | 8 | J I Chela | 3 | 6 | 3 | | | | | |
| | G Cañas | 1 | 0$^r$ | | | | | 4 | A Calleri | 6 | 3 | 6 | | | | | |
| Q | F Verdasco | 6 | 1 | Q | F Verdasco | 4 | 4 | | | | | | | | | | |
| | A Portas | 1 | 3 | 4 | A Calleri | 6 | 6 | | | | | | | | | | |
| 4 | A Calleri | 6 | 6 | | | | | | | | | | 4 | A Calleri | 6 | 5 | 6 |
| 5 | M Zabaleta | 4 | 1 | | | | | | | | | | | L Horna | 4 | 7 | 1 |
| | A Montañés | 6 | 6 | | A Montañés | 2 | 6$^4$ | | | | | | | | | | |
| | D Sánchez | 2 | 6$^4$ | | G Blanco | 6 | 7$^7$ | | | | | | | | | | |
| | G Blanco | 6 | 7$^7$ | | | | | | G Blanco | 1 | 6$^5$ | | | | | | |
| WC | P Braga | 3 | 2 | | | | | | L Horna | 6 | 7$^7$ | | | | | | |
| | L Horna | 6 | 6 | | L Horna | 6 | 6 | | | | | | | | | | |
| Q | J Mónaco | 6 | 6 | Q | J Mónaco | 4 | 1 | | | | | | | | | | |
| 2 | N Massú | 4 | 2 | | | | | | | | | | | | | | |