Ferrero's 6-3, 6-2 victory put him into the semis along with Ricardo Mello, Igor Andreev and Lukasz Kubot.
Mello and Kubot had to win twice Friday while the tournament was getting back on schedule following all-day rains Thursday that wiped out four second-round matches.
Mello pulled off the biggest surprise, defeating third-seeded Thomaz Bellucci 6-3, 7-6 (7-3).
Andreev was a 6-1, 6-2 winner over Pablo Cuevas and Kubot crushed Fabio Fognini 6-3, 6-1.
Megyn Kelly: Santa Claus and Jesus are both white men
Wisconsin business offering 'therapeutic cuddling' forced to close