The part-time Miami resident fought back against second-seeded Karolina Pliskova last night to win 5-7, 6-1, 6-1.
In the final, the Danish No 12 seed will either Britain’s Johanna Konta, seeded 10 or 11th seed Venus Williams of the USA.
Wozniacki, playing at Key Biscayne for the tenth time, was clearly the fresher player as the match went along on an 80-degree sunny afternoon. She wasted three set points in the opening set, then was barely challenged the rest of the way.
“I got a good start to the second set and that kind of got me fired up,” Wozniacki said.
Wozniacki won 62 of the 104 points played in the final two sets, recovering more than nicely after letting the first set get away.
She won the first three games of the second set and then controlled the rest of the match. The former world No 1 went over the $23 million career earnings mark with the win. A win in the final would put her back up to No 8 in the world.
“It’s extremely special,” said Wozniacki. “Having a place here, training here in the offseason, playing kind of on home advantage, it’s special to be in my first finals here. I’m extremely excited.”
It was a rematch of the final at Doha earlier this year, which Pliskova took in straight sets. Now Wozniacki is in her third final of the year, looking for her first crown of 2017 and 26th overall.
In the men’s draw, Rafael Nadal will play Italy’s Fabio Fognini in the semi-finals after a 6-2, 6-3 victory over Jack Sock of the USA. Spaniard Nadal has never won the Miami Open, having lost in the final in 2005, 2008, 2011 and 2014.
Fognini defeated Japan’s Kei Nishikori 6-4, 6-2 to become the first unseeded player in ten years to reach the last four.
Meanwhile, the International Tennis Federation has announced plans to restructure the entry level of the sport and dramatically cut the number of professionals.
Around 14,000 players compete in professional events, almost half not earning any money, according to a three-year review. The ITF would like to reduce that to 750 men and 750 women.
The main plank of the reforms, which have been approved by the ITF board, is a new Transition Tour from 2019. It would replace the lowest level of professional tournaments on the ITF Pro Circuit, with players earning ITF entry points instead of ATP or WTA ranking points.
The two systems will be linked to ensure that the more successful players are able to use their entry points to gain acceptance into higher-level tournaments.
The review found that, in 2013, only the top 336 men and 253 women were earning money once outgoings were taken into account, while the time taken to reach the top 100 had increased substantially.