There looked to be an upset on the cards when home favourite Pella took the first set 6-4 but the Spanish third seed then found his range and came roaring back to progress 4-6 6-1 6-4.
The same could not be said for fellow Spaniard Marcel Granollers who suffered a comprehensive defeat to countryman Pablo Andujar.
The fifth seed made a fight of it in the first set but then capitulated as he slumped to a shock 6-3 6-0 loss.
Daniel Gimeno-Traver was also involved in an all-Spanish tussle as he progressed to the last 16 with a 7-5 6-2 win over Ruben Ramirez Hidalgo.
Fourth seed Nicolas Almagro also moved into the last 16 with a routine win over Horacio Zeballos.
The fourth seed never looked in real danger as he claimed a 6-2 7-5 victory at the expense of the Argentinian.
Jeremy Chardy had no trouble advancing as the eighth-seeded Frenchman beat Alejandro Gonzalez 6-4 7-5 while Alexandr Dolgopolov was a 6-3 4-6 7-6 (7/5) winner over Pablo Cuevas.