1:00 p.m. start
 Anett KONTAVEIT (EST) vs  Ashleigh BARTY (AUS)
Not before 9:00 p.m.
 Karolina PLISKOVA (CZE) vs  Simona HALEP (ROU)
Friday's semifinal match could be a milestone one for Halep: the reigning French Open champion can return to World No.1 should she defeat Pliskova to reach the final in Miami.
The Romanian leads the head-to-head against Pliskova 7-3, with the two former World No.1s set to play for the 11th time. Halep has won four of the last five, including a dramatic three-set clash in Fed Cup earlier this year.
Outside of Halep's ranking quest, Pliskova is already guaranteed to return to World No.4 by virtue of reaching the semifinals.
Kontaveit has already far and away outperformed her best career result in Miami this year. The Estonian reached the third round as a qualifier in 2017, where she was defeated by Halep.
The Estonian has already been assured of cracking the Top 15 by reaching the semifinals, as she seeks to better Kaia Kanepi's career-high ranking of World No.15, which is the high watermark for an Estonian woman in singles.