The second-seeded Brazilian player claimed the opening set, but Boulter dropped 11 straight games before rallying to win the 3-6 6-3 6-4 second-round encounter.
On Friday, she will face either Canada’s Marina Stakusic or Croatia’s Donna Vekic, the 2022 runner-up.
The Mexican Open second round saw British number three Jack Draper defeat Yoshihito Nishioka of Japan 6-3 6-0.
In the first round, Draper defeated Tommy Paul, the seventh seed. In the quarterfinals on Friday, he will play Serb Miomir Kecmanovic, who is ranked 53rd in the world, three spots below Draper.
