# 2005 ATP Buenos Aires – Singles

Gastón Gaudio defeated Mariano Puerta 6–4, 6–4 to win the 2005 ATP Buenos Aires singles competition. Guillermo Coria was the champion but did not defend his title.

## Seeds

* Carlos Moyà (quarterfinals)
* Gastón Gaudio (champion)
* Guillermo Cañas (second round)
* Fernando González (withdrew)
* Juan Ignacio Chela (first round)
* Filippo Volandri (first round)
* Rafael Nadal (quarterfinals)
* Mariano Zabaleta (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

| Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final |
| WC | Mariano Puerta | 6 | 7$^7$ | | | | |
| | José Acasuso | 4 | 6$^5$ | | | | |
| | José Acasuso | 4 | 6$^5$ | WC | Mariano Puerta | 4 | 4 |
| | | | | 2 | Gastón Gaudio | 6 | 6 |
| | Alberto Martín | 3 | 4 | 2 | Gastón Gaudio | 6 | 6 |
| 2 | Gastón Gaudio | 6 | 6 | | | | |

### Top half

| 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 |
| 1 | C Moyà | 6 | 7$^7$ | | | | | | | | | | | | | |
| Q | P Luczak | 3 | 6$^5$ | 1 | C Moyà | 6 | 6 | | | | | | | | | |
| | Á Costa | 5 | 4 | | J Mónaco | 1 | 2 | | | | | | | | | |
| | J Mónaco | 7 | 6 | | | | | | 1 | C Moyà | 6$^0$ | 3 | | | | |
| Q | J-P Guzmán | 2 | 6$^2$ | | | | | | WC | M Puerta | 7$^7$ | 6 | | | | |
| WC | M Puerta | 6 | 7$^7$ | WC | M Puerta | 6 | 6 | | | | | | | | | |
| | L Burgsmüller | 6 | 6 | | L Burgsmüller | 2 | 0 | | | | | | | | | |
| 6 | F Volandri | 4 | 2 | | | | | | | | | | WC | M Puerta | 6 | 7$^7$ |
| LL | G García López | 6 | 6 | | | | | | | | | | | J Acasuso | 4 | 6$^5$ |
| | D Sánchez | 4 | 3 | LL | G García López | 4 | 3 | | | | | | | | | |
| | J Acasuso | 6 | 6 | | J Acasuso | 6 | 6 | | | | | | | | | |
| | P-H Mathieu | 3 | 2 | | | | | | | J Acasuso | 6 | 6 | | | | |
| | S Ventura | 3 | 3 | | | | | | | N Almagro | 3 | 4 | | | | |
| | N Almagro | 6 | 6 | | N Almagro | 6$^4$ | 6 | 6 | | | | | | | | |
| | Á Calatrava | 3 | 2 | 8 | M Zabaleta | 7$^7$ | 4 | 4 | | | | | | | | |
| 8 | M Zabaleta | 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 | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 5 | J I Chela | 5 | 1 | | | | | | | | | | | | | | | |
| Q | M López | 7 | 6 | | Q | M López | 6 | 6$^5$ | 6$^4$ | | | | | | | | | |
| | F Mantilla | 6 | 7$^7$ | | | F Mantilla | 4 | 7$^7$ | 7$^7$ | | | | | | | | | |
| | Ó Hernández | 4 | 6$^0$ | | | | | | | | F Mantilla | 7 | 4 | 6$^3$ | | | | |
| | D Ferrer | 0$^r$ | | | | | | | | | A Martín | 5 | 6 | 7$^7$ | | | | |
| | A Martín | 5 | | | | A Martín | 6 | 6 | | | | | | | | | | |
| | À Corretja | 3 | 1 | | 3 | G Cañas | 4 | 3 | | | | | | | | | | |
| 3 | G Cañas | 6 | 6 | | | | | | | | | | | | | A Martín | 3 | 4 |
| WC/7 | R Nadal | 7$^7$ | 6 | | | | | | | | | | | | 2 | G Gaudio | 6 | 6 |
| | A Calleri | 6$^2$ | 3 | | WC/7 | R Nadal | 6 | 6 | | | | | | | | | | |
| WC | E Massa | 6$^5$ | 0 | | | P Starace | 1 | 3 | | | | | | | | | | |
| | P Starace | 7$^7$ | 6 | | | | | | | WC/7 | R Nadal | 6 | 0 | 1 | | | | |
| | Montañés | 3 | 6 | 2 | | | | | | 2 | G Gaudio | 0 | 6 | 6 | | | | |
| | F Saretta | 6 | 0 | 6 | | F Saretta | 3 | 2 | | | | | | | | | | |
| Q | F Luzzi | 6 | 1 | 3 | 2 | G Gaudio | 6 | 6 | | | | | | | | | | |
| 2 | G Gaudio | 2 | 6 | 6 | | | | | | | | | | | | | | |