Both players broke serve twice in the final set, but the Navarro dominated in the tiebreak to close out in 1 hour, 45 minutes. The match was briefly interrupted in the second set because of rain.
Navarro will face fifth-seeded Monica Niculescu of Romania, who beat qualifier Danka Kovinic of Montenegro 6-3, 6-1.
Third-seeded Klara Zakopalova of the Czech Republic, trying to reach her third final this year, cruised into the quarterfinals with a 6-3, 6-3 win over French qualifier Alize Lim.
Zakopalova, runner up at last week's Rio Open, will face Alexandra Dulgheru of Romania, who defeated Brazilian Teliana Pereira 7-5, 6-2.