Venus Williams overcame world number one Angelique Kerber to set up a Miami Open semi-final against Johanna Konta.
Williams, bidding for her 50th WTA Tour title, reached the last four with a hard-fought 7-5 6-3 win over Kerber on Wednesday.
The American seven-time grand-slam champion broke Kerber's serve five times on her way to the semi-finals.
Williams, also a three-time winner in Miami, and Kerber traded breaks twice in the first set before the 11th seed claimed the decisive one in the 12th game.
Although she was broken in the opening game of the second set, Williams rolled out to a 4-1 lead before sealing her win.
KONTA WINS HALEP BATTLE
Awaiting her is 10th seed Konta, who upset Simona Halep 3-6 7-6 (9-7) 6-2 after two and a half hours.
The Romanian third seed dominated from the baseline early before Konta fought back, a rollercoaster tie-break going the Brit's way.
Konta took the momentum into the third and from 2-1 down powered through the final five games.
She holds a 2-1 head-to-head record over Williams, including winning their two matches last year.