Ferrer, who received a first-round bye, is bidding to win his third Bastad title following wins in 2007 and 2012. He next meets defending champion Carlos Berlocq of Argentina, who defeated qualifier Radu Albot of Moldova 5-7, 6-4, 6-2.
Third-seeded Fernando Verdasco, the runner-up in Bastad last year, ousted Spanish countryman Albert Ramos-Vinolas 6-1, 7-5.
Verdasco will face another countryman, eighth-seeded Pablo Carreno Busta, in the last eight. Carreno Busta beat Paolo Lorenzi of Italy 6-2, 6-2.
The other quarters feature Joao Sousa vs. Dusan Lajovic, and Pablo Cuevas vs. Renzo Olivo.