2015 finalist Madison Keys, fended off Monica Puig 6-4 6-0 in a rain-interrupted semifinal on the Charleston clay.
American eighth seed Keys overcame a rain delay of almost one-and-a-half hours as she prevailed in just 85 minutes against the 2016 Olympic champion.
"Can't wait to play tomorrow. I feel really comfortable on clay, especially on green clay, and playing here. I am just so happy I get to play another final here", mentioned Keys after defeating Puig.
Former world number one and 2018 Australian Open champion Caroline Wozniacki awaits. Wozniacki moved through to the Charleston final thanks to Saturday's 6-3 6-4 win over Petra Martic.