Fourth seed Elena Rybakina moved into the Miami final for the second straight year with a gutsy win against Victoria Azarenka in a deciding tie-break.
Kazakhstan's Rybakina, 24, recovered from an awful second set to win 6-4 0-6 7-6 (7-1) against the Belarusian.
Rybakina showed resilience in the final stages, having led 5-3 before losing serve at 5-4 as Azarenka levelled.
The 2022 Wimbledon champion will face unseeded Danielle Collins or 14th seed Ekaterina Alexandrova in the final.
Last year, Rybakina was beaten by Czech Petra Kvitova to the trophy as she aimed to complete the 'Sunshine Double' of back-to-back titles in Indian Wells and Miami.