# 2004 Siebel Open – Singles

Andre Agassi was the defending champion but lost in the semifinals to Mardy Fish.
Andy Roddick won in the final 7–6$^{(15–13)}$, 6–4 against Fish.

## Seeds

A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated.
* Andy Roddick (champion)
* Andre Agassi (semifinals)
* Mardy Fish (final)
* Taylor Dent (second round)
* Robby Ginepri (second round)
* Vince Spadea (second round)
* James Blake (second round)
* Wayne Ferreira (first 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
| 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 | Semifinals | Final | Final | Final | Final |
| 1 | A Roddick | 6 | 6 | | | | | | | | | | | | | | | | | | | | |
| | C Rochus | 4 | 2 | | 1 | A Roddick | 6 | 6 | | | | | | | | | | | | | | | |
| | K Vliegen | 6 | 6 | | | K Vliegen | 2 | 3 | | | | | | | | | | | | | | | |
| | A Popp | 1 | 3 | | | | | | | 1 | A Roddick | 6 | 7$^9$ | | | | | | | | | | |
| | N Kiefer | 7 | 5 | 2 | | | | | | | J Johansson | 3 | 6$^7$ | | | | | | | | | | |
| | J Johansson | 5 | 7 | 6 | | J Johansson | 6 | 6 | | | | | | | | | | | | | | | |
| Q | Z Fleishman | 1 | 3 | | 7 | J Blake | 4 | 2 | | | | | | | | | | | | | | | |
| 7 | J Blake | 6 | 6 | | | | | | | | | | | | 1 | A Roddick | 7$^7$ | 6 | | | | | |
| 4 | T Dent | 6 | 6 | | | | | | | | | | | | WC | R Kendrick | 6$^3$ | 2 | | | | | |
| | P Goldstein | 4 | 4 | | 4 | T Dent | 4 | 4 | | | | | | | | | | | | | | | |
| WC | R Kendrick | 6 | 6 | | WC | R Kendrick | 6 | 6 | | | | | | | | | | | | | | | |
| | L Burgsmüller | 4 | 2 | | | | | | | WC | R Kendrick | 7$^8$ | 4 | 6 | | | | | | | | | |
| | C Saulnier | 6 | 7$^7$ | | | | | | | | C Saulnier | 6$^6$ | 6 | 3 | | | | | | | | | |
| | B Vahaly | 3 | 6$^4$ | | | C Saulnier | 3 | 7 | 6 | | | | | | | | | | | | | | |
| Q | C Mamiit | 4 | 3 | | WC/5 | R Ginepri | 6 | 5 | 4 | | | | | | | | | | | | | | |
| WC/5 | R Ginepri | 6 | 6 | | | | | | | | | | | | | | | | | 1 | Andy Roddick | 7$^{15}$ | 6 |
| 6 | V Spadea | 6 | 6 | | | | | | | | | | | | | | | | | 3 | Mardy Fish | 6$^{13}$ | 4 |
| WC | T Haas | 4 | 2 | | 6 | V Spadea | 6 | 4 | 4 | | | | | | | | | | | | | | |
| | H-T Lee | 7$^7$ | 6 | | | H-T Lee | 2 | 6 | 6 | | | | | | | | | | | | | | |
| | X Malisse | 6$^1$ | 1 | | | | | | | | H-T Lee | 2 | 3 | | | | | | | | | | |
| | J Melzer | 3 | 6 | 3 | | | | | | | M Fish | 6 | 6 | | | | | | | | | | |
| | K Carlsen | 6 | 4 | 6 | | K Carlsen | 3 | 6 | 6$^2$ | | | | | | | | | | | | | | |
| Q | A Reichel | 1 | 4 | | 3 | M Fish | 6 | 3 | 7$^7$ | | | | | | | | | | | | | | |
| 3 | M Fish | 6 | 6 | | | | | | | | | | | | 3 | M Fish | 5 | 6 | 6 | | | | |
| 8 | W Ferreira | 7$^{14}$ | 6$^5$ | 1 | | | | | | | | | | | 2 | A Agassi | 7 | 4 | 2 | | | | |
| | J-M Gambill | 6$^{12}$ | 7$^7$ | 6 | | J-M Gambill | 6 | 6 | | | | | | | | | | | | | | | |
| | D Tursunov | 5 | 6 | 3 | Q | K. J. Hippensteel | 3 | 2 | | | | | | | | | | | | | | | |
| Q | K. J. Hippensteel | 7 | 4 | 6 | | | | | | | J-M Gambill | 6$^4$ | 5 | | | | | | | | | | |
| | W Moodie | 6 | 7$^7$ | | | | | | | 2 | A Agassi | 7$^7$ | 7 | | | | | | | | | | |
| | T Martin | 4 | 6$^1$ | | | W Moodie | 6$^6$ | 4 | | | | | | | | | | | | | | | |
| | I Labadze | 6$^4$ | 4 | | 2 | A Agassi | 7$^8$ | 6 | | | | | | | | | | | | | | | |
| 2 | A Agassi | 7$^7$ | 6 | | | | | | | | | | | | | | | | | | | | |