Ferrer will next play South Africa’s Kevin Anderson, who ousted American Sam Querrey, 7-6 (2), 6-4, reports Xinhua.
Sixth-seeded Gilles Simon of France beat Donald Young of the US 6-4, 6-3.
Ukraine’s Alexandr Dolgopolov eliminated Frenchman Jeremy Chardy 6-3, 6-4 and Croatia’s Ivo Karlovic defeated Dudi Sela of Israel 7-6 (4), 6-2.
Top-seeded Dominika Cibulkova also secured a berth in the quarterfinals with a 7-5, 6-2 win over Yanina Wickmayer of Belgium in the women’s category.
Cibulkova has won her first matches on tour since her run to the Australian Open final and is due to play Marina Erakovic of New Zealand, who defeated Serbia’s Bojana Jovanovski 6-1, 6-4.
Eighth-seeded Zhang Shuai of China beat Canada’s Aleksandra Wozniak 6-1, 6-4.
America’s Christina McHale knocked out Kimiko Date-Krumm of Japan 7-5, 6-1.
Croatia’s Ajla Tomljanovic downed Victoria Duval of the United States 6-3, 6-0.
Caroline Garcia of France outlasted Sharon Fichman of Canada 6-2, 7-5.