| 11‑Jul‑2003 | Davis Cup G1 PO: VEN vs CHI | Hard | RR | 44 | 324 | Jose De Armas [VEN] d. Rios | 7-5 6-2 3-6 3-6 8-6 | | | | | | | | | |
| 11‑Jul‑2003 | Davis Cup G1 PO: VEN vs CHI | Hard | RR | 44 | 475 | Kepler Orellana [VEN] d. Rios | 7-6(4) RET | | | | | | | | | |
| 26‑May‑2003 | Roland Garros | Clay | R128 | 42 | 74 | Mario Ancic [CRO] d. Rios | 6-1 1-0 RET | | 0.37 | 0.0% | 3.2% | 51.6% | 56.3% | 26.7% | 2/5 | 0:36 |
| 19‑May‑2003 | Dusseldorf | Clay | F | 42 | 47 | Radek Stepanek [CZE] d. Rios | 6-3 7-6(5) | | 0.82 | 0.0% | 3.5% | 59.3% | 54.9% | 54.3% | 9/12 | 1:43 |
| 19‑May‑2003 | Dusseldorf | Clay | RR | 42 | 22 | Rios d. Gaston Gaudio [ARG] | 6-3 6-3 | | 1.24 | 3.0% | 1.5% | 52.2% | 65.7% | 50.0% | 11/13 | 1:15 |
| 19‑May‑2003 | Dusseldorf | Clay | RR | 42 | 102 | Tomas Behrend [GER] d. Rios | 3-6 7-5 7-6(2) | | 0.97 | 5.7% | 0.9% | 59.4% | 69.8% | 53.5% | 5/8 | 2:22 |
| 17‑Mar‑2003 | Miami Masters | Hard | R16 | 31 | 13 | (13)Paradorn Srichaphan [THA] d. (28)Rios | W/O | | | | | | | | | |
| 17‑Mar‑2003 | Miami Masters | Hard | R32 | 31 | 3 | (28)Rios d. (3)Juan Carlos Ferrero [ESP] | 6-3 7-6(2) | | 1.37 | 8.7% | 5.8% | 68.1% | 74.5% | 54.5% | 2/3 | 1:38 |
| 17‑Mar‑2003 | Miami Masters | Hard | R64 | 31 | 41 | (28)Rios d. Taylor Dent [USA] | 6-1 6-1 | | 1.79 | 6.4% | 0.0% | 68.1% | 75.0% | 53.3% | 2/2 | 0:59 |
| 10‑Mar‑2003 | Indian Wells Masters | Hard | R32 | 29 | 36 | Max Mirnyi [BLR] d. Rios | 6-3 6-3 | | 0.62 | 2.9% | 5.7% | 72.9% | 60.8% | 42.1% | 6/9 | 1:02 |
| 10‑Mar‑2003 | Indian Wells Masters | Hard | R64 | 29 | 20 | Rios d. (17)Gaston Gaudio [ARG] | 4-0 RET | | - | 12.5% | 0.0% | 50.0% | 100.0% | 100.0% | 0/0 | 0:14 |
| 3‑Mar‑2003 | Delray Beach | Hard | SF | 30 | 66 | Mardy Fish [USA] d. (3)Rios | 6-3 6-4 | | 0.70 | 7.5% | 5.7% | 64.2% | 64.7% | 57.9% | 3/5 | 1:08 |
| 3‑Mar‑2003 | Delray Beach | Hard | QF | 30 | 63 | (3)Rios d. Hyung Taik Lee [KOR] | 6-3 6-4 | | 1.32 | 10.0% | 0.0% | 60.0% | 66.7% | 58.3% | 6/8 | 1:20 |
| 3‑Mar‑2003 | Delray Beach | Hard | R16 | 30 | 67 | (3)Rios d. Martin Verkerk [NED] | 2-6 6-4 7-5 | | 1.05 | 7.0% | 3.5% | 57.0% | 77.6% | 54.1% | 3/5 | 1:52 |
| 3‑Mar‑2003 | Delray Beach | Hard | R32 | 30 | 111 | (3)Rios d. Jeff Morrison [USA] | 6-3 6-3 | | 1.64 | 5.5% | 1.8% | 58.2% | 84.4% | 56.5% | 5/6 | 0:59 |
| 24‑Feb‑2003 | Acapulco | Clay | QF | 32 | 61 | Agustin Calleri [ARG] d. (7)Rios | 6-3 7-5 | | 0.68 | 8.8% | 10.0% | 67.5% | 61.1% | 34.6% | 12/17 | 1:13 |
| 24‑Feb‑2003 | Acapulco | Clay | R16 | 32 | 154 | (7)Rios d. (LL)Juan Antonio Marin [CRC] | 6-3 6-1 | | 2.00 | 4.7% | 4.7% | 55.8% | 87.5% | 52.6% | 0/1 | 0:48 |
| 24‑Feb‑2003 | Acapulco | Clay | R32 | 32 | 85 | (7)Rios d. Franco Squillari [ARG] | 2-6 6-0 6-4 | | 1.33 | 4.3% | 1.4% | 73.9% | 74.5% | 38.9% | 1/3 | 1:57 |
| 10‑Feb‑2003 | Vina del Mar | Clay | F | 37 | 57 | David Sanchez [ESP] d. (3)Rios | 1-6 6-3 6-3 | | 0.92 | 2.3% | 2.3% | 66.3% | 54.4% | 65.5% | 6/10 | 1:42 |
| 10‑Feb‑2003 | Vina del Mar | Clay | SF | 37 | 22 | (3)Rios d. (1)Gaston Gaudio [ARG] | 6-3 6-2 | | 1.80 | 13.3% | 2.2% | 71.1% | 84.4% | 46.2% | 0/1 | 1:06 |
| 10‑Feb‑2003 | Vina del Mar | Clay | QF | 37 | 46 | (3)Rios d. (5)Agustin Calleri [ARG] | 6-4 7-6(2) | | 1.26 | 0.0% | 4.1% | 70.3% | 65.4% | 59.1% | 4/7 | 1:48 |
| 10‑Feb‑2003 | Vina del Mar | Clay | R16 | 37 | 94 | (3)Rios d. Albert Portas [ESP] | 6-4 7-6(3) | | 1.30 | 7.2% | 1.4% | 75.4% | 75.0% | 41.2% | 5/7 | 1:28 |
| 10‑Feb‑2003 | Vina del Mar | Clay | R32 | 37 | 424 | (3)Rios d. (WC)Adrian Garcia [CHI] | 6-3 6-2 | | 2.17 | 6.4% | 2.1% | 74.5% | 88.6% | 50.0% | 0/0 | 0:55 |
| 7‑Feb‑2003 | Davis Cup G1 R1: ECU vs CHI | Clay | RR | 37 | 267 | Giovanni Lapentti [ECU] d. Rios | 6-3 7-6(5) 6-3 | | | | | | | | | |
| 7‑Feb‑2003 | Davis Cup G1 R1: ECU vs CHI | Clay | RR | 37 | 33 | Rios d. Nicolas Lapentti [ECU] | 3-6 6-4 7-6(0) 7-6(5) | | | | | | | | | |