| 25‑Aug‑2003 | US Open | Hard | R128 | 222 | 15 | (15)Fernando Gonzalez [CHI] d. (WC)Chang | 6-3 7-5 5-7 6-4 | | 0.96 | 8.4% | 2.8% | 57.9% | 77.4% | 55.6% | 2/6 | 2:27 |
| 18‑Aug‑2003 | Long Island | Hard | R32 | 223 | 189 | (Q)Rik De Voest [RSA] d. (WC)Chang | 6-2 6-3 | | 0.53 | 1.4% | 2.9% | 44.9% | 61.3% | 47.4% | 5/9 | 1:15 |
| 11‑Aug‑2003 | Cincinnati Masters | Hard | R64 | 217 | 79 | (Q)Hicham Arazi [MAR] d. (WC)Chang | 4-6 7-6(7) 6-0 | | 0.76 | 3.8% | 4.7% | 54.7% | 60.3% | 45.8% | 6/12 | 2:19 |
| 28‑Jul‑2003 | Los Angeles | Hard | R16 | 168 | 20 | (5)Mark Philippoussis [AUS] d. Chang | 6-2 6-4 | | 0.53 | 7.1% | 0.0% | 55.4% | 64.5% | 32.0% | 2/6 | 1:14 |
| 28‑Jul‑2003 | Los Angeles | Hard | R32 | 168 | 252 | Chang d. (Q)Zack Fleishman [USA] | 6-1 6-1 | | 1.94 | 10.3% | 2.6% | 66.7% | 80.8% | 46.2% | 0/1 | 0:50 |
| 21‑Jul‑2003 | Indianapolis | Hard | R64 | 173 | 147 | Eric Taino [PHI] d. Chang | 3-6 6-3 7-5 | | 1.06 | 13.4% | 0.0% | 58.5% | 79.2% | 52.9% | 1/3 | 2:13 |
| 14‑Jul‑2003 | Aptos CH | Hard | R32 | 161 | 137 | (6)Sergio Roitman [ARG] d. Chang | 6-2 7-6(3) | | | | | | | | | |
| 26‑May‑2003 | Roland Garros | Clay | R128 | 142 | 54 | Fabrice Santoro [FRA] d. (WC)Chang | 7-5 6-1 6-1 | | 0.65 | 1.1% | 2.2% | 51.6% | 57.4% | 38.6% | 5/12 | 2:05 |
| 12‑May‑2003 | Forest Hills CH | Clay | R16 | 144 | 419 | (LL)Tripp Phillips [USA] d. Chang | 4-6 6-4 6-3 | | | | | | | | | |
| 12‑May‑2003 | Forest Hills CH | Clay | R32 | 144 | 237 | Chang d. Jose De Armas [VEN] | 6-4 3-6 6-2 | | | | | | | | | |
| 17‑Mar‑2003 | Miami Masters | Hard | R64 | 122 | 2 | (2)Andre Agassi [USA] d. (WC)Chang | 6-4 6-2 | | 0.63 | 6.3% | 1.6% | 52.4% | 69.7% | 43.3% | 2/5 | 1:27 |
| 17‑Mar‑2003 | Miami Masters | Hard | R128 | 122 | 74 | (WC)Chang d. Nicolas Kiefer [GER] | 6-2 6-2 | | 2.20 | 15.9% | 0.0% | 59.1% | 92.3% | 55.6% | 0/0 | 1:03 |
| 10‑Mar‑2003 | Indian Wells Masters | Hard | R64 | 119 | 5 | (5)Carlos Moya [ESP] d. (WC)Chang | 6-0 6-3 | | 0.58 | 2.5% | 5.0% | 57.5% | 47.8% | 41.2% | 2/6 | 1:03 |
| 17‑Feb‑2003 | Memphis | Hard | R32 | 120 | 13 | (2)Paradorn Srichaphan [THA] d. (WC)Chang | 6-4 6-2 | | 0.58 | 4.1% | 4.1% | 61.2% | 70.0% | 47.4% | 0/3 | 0:56 |
| 10‑Feb‑2003 | San Jose | Hard | R32 | 119 | 2 | (1)Andre Agassi [USA] d. (WC)Chang | 6-4 6-2 | | 0.40 | 13.7% | 2.0% | 54.9% | 67.9% | 47.8% | 1/4 | 1:03 |