The fourth-seeded Medina Garrigues downed Taiwan's Hsieh 7-6 (11-9), 7-6 (7-2) at Strasbourg Tennis Club in France, where she has claimed titles in 2005, 2007 and 2008.
Waiting for her will be wild card Alize Cornet, who rallied for a 4-6, 6-4, 6-0 win over Israeli Shahar Peer.
Also reaching the Round of 8 was second-seeded 2010 French Open champ Francesca Schiavone, who dispatched Croatian qualifier Mirjana Lucic 6-1, 6-2.
She'll next face Johanna Larsson of Sweden, who upset eighth-seeded Austrian Tamira Paszek 6-2, 6-0 on Day 3.
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