Angelique Kerber and Victoria Azarenka will compete for a spot in the Miami Open final after victories in their respective quarter-finals on Wednesday.
Second seed Kerber was largely untroubled by Madison Keys and eased past the American 6-3 6-2 at the WTA Premier tournament.
Azarenka was also victorious in straight-sets, defeating Brit Johanna Konta 6-4 6-2 earlier in the day.
KERBER BOOKS MAIDEN SEMI SPOT
World number three Kerber has responded well from her early exit at Indian Wells but faced tough tests in her road to the quarter-finals.
However, against Keys, Kerber was back to her dominant best and she needed just one hour, eight minutes to get past the American in Key Biscayne.
Kerber broke twice in each set, while Keys made a total of 39 unforced errors compared to the German's 11.
The win moves 2016 Australian Open winner Kerber into the semi-finals in Miami for the first time as she looks for a ninth career WTA title.
FIRST SEMI IN FIVE YEARS FOR AZARENKA
Azarenka, who was crowned Indian Wells champion, was clinical in her performance against Konta.
The Belarusian made it to the semi-finals in Miami for the first time since 2011, when she defeated Maria Sharapova in the final.
The two-time winner at the tournament saved five break points in the clash.
AZARENKA: KERBER'S BOGEY?
The two have faced each other seven times in their careers, but Azarenka has the clear advantage.
Azarenka has claimed six victories compared to Kerber's one, but that was their most recent meeting in the quarter-finals of the Australian Open.
"I won against her for my first time and I know that I must play my best tennis against her," Kerber said. "We've had great battles in the past. I will go out to try and enjoy the semis, and I will be ready."
Timea Bacsinszky and Svetlana Kuznetsova are in action on Thursday to determine who becomes the first player into the Miami Open final before Azarenka and Kerber do battle.