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| Vale Do Lobo $10,000 Hard | Feb 8 2004 |
| Qual 1 | Lopez-Herrera - Claudia Oliveira | 6-0 6-0 |
| Qual 2 | Alexandra Recio - Lopez-Herrera | 7-60 6-1 |
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| Albufeira $10,000 Hard | Feb 15 2004 |
| Qual 1 | Lopez-Herrera - Nikol Dimitrova | 5-7 4-1 |
| Qual 2 | Lopez-Herrera - Sara Del Barrio Aragon | 6-3 6-73 6-2 |
| Qual 3 | Flavia Mignola(3) - Lopez-Herrera | 6-4 2-6 6-1 |
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| Portimao $10,000 Hard | Feb 22 2004 |
| Qual 1 | Lopez-Herrera - Veronica Saucedo | 6-2 6-1 |
| Qual 2 | Giulia Meruzzi(15) - Lopez-Herrera | 7-5 6-0 |
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| Acapulco Tier III Clay | Mar 7 2004 |
| Qual 1 | Marie-Eve Pelletier - Lopez-Herrera-WC | 6-4 6-1 |
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| Monterrey $10,000 Hard | Mar 28 2004 |
| 1 | Patricia Holzman-Q - Lopez-Herrera-WC | 6-1 6-0 |
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| Poza Rica $25,000 Hard | Apr 25 2004 |
| 1 | Erica Biro - Lopez-Herrera-WC | 6-0 6-2 |
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| Coatzacoalcos $25,000 Hard | May 2 2004 |
| Qual 1 | Giorgia Mortello(10) - Lopez-Herrera-WC | 6-3 6-1 |
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| Merida $10,000 Hard | May 9 2004 |
| Qual 1 | Mami Inoue - Lopez-Herrera | 6-4 6-1 |
| 1 | Maria Wolfbrandt(3) - Lopez-Herrera-LL | 6-3 6-2 |
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| El Paso $10,000 Hard | May 23 2004 |
| Qual 1 | Lopez-Herrera(3) | bye |
| Qual 2 | Lopez-Herrera(3) - Lindsey Jones | 6-2 6-2 |
| Qual 3 | Lopez-Herrera(3) - Monica Rincon | 6-1 6-0 |
| 1 | Lopez-Herrera-Q - Bianca Acquistapace | 6-1 1-6 6-3 |
| 2 | Cindy Watson(4) - Lopez-Herrera-Q | 6-1 6-3 |
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| Houston $10,000 Hard | May 30 2004 |
| Qual 1 | Lopez-Herrera(10) | bye |
| Qual 2 | Lopez-Herrera(10) - Christine Alford | 6-0 6-2 |
| Qual 3 | Andrea Remynse - Lopez-Herrera(10) | 6-3 6-3 |
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| Hilton Head $10,000 Hard | Jun 6 2004 |
| Qual 1 | Lopez-Herrera(8) | bye |
| Qual 2 | Lopez-Herrera(8) - Melody Snelen | 6-2 6-0 |
| Qual 3 | Lopez-Herrera(8) - Nikola Hubnerova | 6-3 6-4 |
| Qual 4 | Lopez-Herrera(8) - Kelly Anderson | 6-1 6-4 |
| 1 | Alexa Glatch-Q - Lopez-Herrera-Q | 6-1 6-1 |
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| Hamilton $25,000 Clay | Jun 13 2004 |
| Qual 1 | Lopez-Herrera(13) - Karin Lems | 6-0 6-1 |
| Qual 2 | Lopez-Herrera(13) - Mami Inoue | 6-1 6-2 |
| 1 | Lopez-Herrera-Q - Lauren Cheung | 1-6 6-2 7-5 |
| 2 | Stephanie Dubois(2)-Q - Lopez-Herrera-Q | 6-1 6-3 |
| | |
| Mont-Tremblant $10,000 Clay | Jun 20 2004 |
| Qual 1 | Lopez-Herrera(5) | bye |
| Qual 2 | Lopez-Herrera(5) - Mami Inoue | 6-4 6-3 |
| 1 | Tomoko Dokei(4) - Lopez-Herrera-Q | 6-3 3-6 6-3 |
| | |
| Campos Do Jordao $25,000 Hard | Jul 18 2004 |
| Qual 1 | Lopez-Herrera(5) - Gabriela Rangel | 6-1 6-2 |
| Qual 2 | Lopez-Herrera(5) - Suzana Dos Anjos | 6-2 6-4 |
| Qual 3 | Lopez-Herrera(5) - Florentina Hanisch(12) | 6-4 6-3 |
| 1 | Katalin Marosi(4) - Lopez-Herrera-Q | 3-6 7-5 6-1 |
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| Ancona $10,000 Clay | Jul 25 2004 |
| 1 | Cristina Celani-Q - Lopez-Herrera | 6-4 7-63 |
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| Dublin $10,000 Carpet | Aug 1 2004 |
| 1 | Lopez-Herrera - Anne-Marie Hogan | 2-6 6-4 6-4 |
| 2 | Dubravka Cupac(7) - Lopez-Herrera | 6-1 6-0 |
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| Wrexham $10,000 Hard | Aug 8 2004 |
| 1 | Lopez-Herrera - Alice MacKenzie | 5-7 6-1 6-2 |
| 2 | Lopez-Herrera - Karen Paterson(6) | 6-4 7-5 |
| QF | Irina Bulykina(1) - Lopez-Herrera | 6-1 6-0 |
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| Mexico City $10,000 Hard | Sep 5 2004 |
| 1 | Lopez-Herrera(6) - Joyce Martinez-WC | 6-4 6-2 |
| 2 | Lopez-Herrera(6) - Virginia Donda | 6-2 6-3 |
| QF | Lopez-Herrera(6) - Daniela Munoz Gallegos(2) | 7-5 6-1 |
| SF | Lopez-Herrera(6) - Melissa Torres Sandoval | 6-2 6-3 |
| F | Julia Cohen(8) - Lopez-Herrera(6) | 6-4 6-4 |
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| CD Victoria $10,000 Hard | Sep 12 2004 |
| 1 | Lopez-Herrera(5) - Yamile Fors Guerra-Q | 7-5 7-66 |
| 2 | Lopez-Herrera(5) - Talitha De Groot-Q | 6-1 6-2 |
| QF | Lopez-Herrera(5) - Elizabeth Kaufman | 6-3 6-0 |
| SF | Tamara Encina-Q - Lopez-Herrera(5) | 7-66 6-2 |
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| Albuquerque $75,000 Hard | Sep 26 2004 |
| Qual 1 | Amanda Johnson - Lopez-Herrera(6) | 6-4 6-3 |
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| Birmingham $25,000 Clay | Oct 3 2004 |
| Qual 1 | Lopez-Herrera(2) | bye |
| Qual 2 | Lopez-Herrera(2) - Ashley Bentley-WC | 7-62 6-1 |
| 1 | Lopez-Herrera-Q - Megha Vakharia | 7-5 6-2 |
| 2 | Katarina Kachlikova(6) - Lopez-Herrera-Q | 6-2 6-1 |
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| CD.Juarez $25,000 Clay | Oct 10 2004 |
| Qual 1 | Lopez-Herrera(2) | bye |
| Qual 2 | Lopez-Herrera(2) - Diane Filip | 6-0 6-1 |
| 1 | Daniela Munoz Gallegos - Lopez-Herrera-Q | 6-4 2-2 |
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| Mexico City $10,000 Hard | Nov 14 2004 |
| 1 | Valentina Castro - Lopez-Herrera(8) | 7-5 7-64 |
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| Puebla $25,000 Hard | Nov 21 2004 |
| Qual 1 | Lopez-Herrera(5) - Elizabeth Kaufman-WC | 3-6 6-2 7-5 |
| Qual 2 | Hannah Collin(10) - Lopez-Herrera(5) | 6-4 1-6 6-4 |
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| San Luis Potosi $25,000 Hard | Nov 28 2004 |
| 1 | Lopez-Herrera-WC - Karen Paterson | 6-72 6-4 7-62 |
| 2 | Melinda Czink(2) - Lopez-Herrera-WC | 6-1 6-1 |
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| Palm Beach Gardens $50,000 Clay | Dec 5 2004 |
| Qual 1 | Kateryna Bondarenko(7) - Lopez-Herrera | 6-0 6-1 |