After losing the second set and trailing 2-3 in the third set, Ferrer won three straight games to get the upperhand at 5-3. Saraza made it 4-5 with a break on the ninth game but Ferrer broke him back on the next game to wrap up the match after two hours.
Ferrer set up a meeting against second seed Korean Kim Ki-Hoon, who breezed past Filipino compatriot Kyle Cordero, 6-0, 6-1.
Top seed Filipino Francis Casey Alcantara outclassed Paul Nicole Magaway, 6-1, 6-1, and sixth seed compatriot Akio Sy downed Japanese Takamasa Takizawa, 6-2, 6-1, while No. 3 Nuttorn Tanchainant of Thailand outplayed Filipino Marco Suntay, 6-3, 6-3, to also earn quarterfinal berths in this tournament sponsored by the Federation of Filipino-Chinese Chamber of Commerce and Industry, Inc. and Wilson balls.
Alcantara will next play No. 5 Korean Jeong Joo-Wook, a 6-4, 6-3 winner over Japanese Rikuto Furuta, Sy will face No. 4 Korean Noh Sang-Woo, who scored a 6-0, 6-2 win over Filipino Roman Floreza, while Tanchainant will meet unseeded Rayadi Surya of Indonesia, who ousted No. 8 Korean Yoon Sun-Hong, 6-0, 6-1.
In the girls singles, top seed Filipino Noelle Nikki Zoleta blasted compatriot Enah Baba, 6-0, 6-0, to advance in the quarters against sixth seed Japanese Fumika Kumagai, a 6-3, 6-1 winner over Filipino Mary Grace Rivero.