Ferrer, seeded No. 1 in this event and seeking the 20th championship of his career, had no trouble disposing of sixth-seeded Fabio Fognini.
Tommy Robredo will meet Ferrer in the semifinals after defeating Julian Reister 6-3, 6-2.
Almagro won over Federico Delbonis 6-1, 7-6 (7-3) and Wawrinka took out Albert Ramos 7-6 (7-4), 6-4.
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