Four-times Grand Slam winner Naomi Osaka fired off 18 aces as the Japanese former world number beat Swiss Belinda Bencic 4-6, 6-3, 6-4 on Thursday to reach her first Miami Open final.
Osaka will take on second seed Iga Swiatek in the final, after the Pole defeated American Jessica Pegula in the semi-final.
Swiatek, who will become world number one on Monday, claimed her 16th straight win with a 6-2, 7-5 victory over Pegula to reach a third straight WTA 1000 final.
She conceded only two first-serve points in the first set but was unable to convert when it counted as Olympic champion Bencic saved a pair of break points in the second game.
Osaka, who had not dropped a set in the tournament, then lost her serve in the third game and again in the fifth.
The pair traded breaks early in the second set before Osaka seized the momentum after breaking in the sixth game.
"She had a really amazing service return - there were times I thought that I hit great serves but she just hit winners," Osaka said.
"(I was) just battling my inner thoughts and trying to know that I must play one point at a time and, you know, adjust if I have to but try not to overwhelm myself with my thoughts."
Osaka saved five of six break points in the third before closing out the match with an ace and a grin, having reached her first final since her second Australian Open title a year ago.
"I feel like if I was negative for a split second I would have lost the match today," said Osaka, who will play in her fourth WTA 1000 showpiece match on Saturday.
"I have to keep pumping myself up and I haven't played as many matches as a lot of these other players so I just have to keep learning."
Swiatek sailed through the opening set but had to fight back from an early break down in the second. She squandered two match points at 5-4 before sealing victory two games later.
The 21-year-old is the first player to make back-to-back finals at Indian Wells and Miami since Victoria Azarenka won the 'Sunshine Double' in 2016.
Swiatek has faced Osaka only once, with the Japanese player winning in straight sets at Toronto in 2019.
"My second match on the WTA Tour, when I felt I am doing a breakthrough, was against her (Osaka)," said Swiatek, who will go top of the rankings following Ash Barty's retirement.
"Even though I lost that match, it inspired me to work harder because she was number one back then. Right now I feel like I am on a different level, so I can actually compete ... We'll see how it is going to go. I'm really excited."