The Polish world No. 2 defeated the unseeded Spaniard 6-2, 7-5 in the second round on Friday.
Świątek will now face Belgium's Elise Mertens for a place in the round of 16.
Poland’s 34th-ranked Magda Linette has also made it through to the last 32 of the Miami Open, with a 7-6, 6-2 victory over Russia's Ekaterina Alexandrova.
She will next take on Czech Linda Fruhvirtová.
Meanwhile, Poland's world No. 27 Magdalena Fręch made an early exit from the Miami Open after losing 4-6, 4-6 to Romanian Elena-Gabriela Ruse in the second round.
The 2025 Miami Open runs until March 30.
(gs)
Source: IAR, PAP