Brisbane - Ukraine's Elina Svitolina stunned second seed Karolina Pliskova on Friday to reach her first Brisbane International final in four attempts.
After falling at the semi-final stage in her previous two attempts - including a loss last year to eventual champion Pliskova - Svitolina recovered from 0-4 down in the first set to win 7-5, 7-5.
She mastered the huge Pliskova serve and out-hit her Czech opponent from the back of the court.
Svitolina also showed admirable mental strength when after squandering a 5-2 second set lead and allowing Pliskova to level at 5-5, she broke once more and held on to win on her fourth match point.
"Karolina plays very well here in Brisbane and playing against the defending champion is always tough," she said.
"I was playing very badly, I was making lots of mistakes so I just said to myself try to take time, just go for your shots, but one metre inside the court."
Svitolina won five tournaments on the WTA tour in 2017, the most of any player, and firmly established herself as a top 10 player.
She started the week two places below Pliskova at number six in the world but will end it ranked fourth, two places higher than her Czech opponent, who will now drop to sixth.
The Ukrainian will also go into Saturday's decider against Belarusian qualifier Aliaksandra Sasnovich as firm favourite to win her 10th title.
Sasnovich earlier became the first qualifier ever to reach the final in Brisbane when she beat seventh-seeded Latvian Anastasija Sevastova.
The 23-year-old Sasnovich outlasted Sevastova 7-6 (7/3), 6-4 in 93 minutes.
Sasnovich has had a gruelling tournament so far, coming through three qualifying rounds and four main-draw matches to reach the final.
In four of those matches, she needed to come from a set down, and had spent over 10 hours on court before her semi-final.
She is also playing with both thighs heavily strapped and has needed injury timeouts in her last three matches.
However, the Belarusian showed no signs of fatigue during the first set and was stronger than Sevastova in the tiebreaker, taking an early lead and holding on to win the first set.
The second set went with serve until 4-4 when Sasnovich attacked with some powerful returns to break the Latvian.
She then comfortably held her own serve to book a spot in the final.
"It was a very good match and I'm really happy to finish in two sets," Sasnovich said.
"It was very close with Anastasija. We play at the same level."
Results of matches
played at the ATP/WTA Brisbane International tennis tournament at the
Queensland Tennis Centre on Friday (X denotes seed):
Alex de Minaur (AUS) bt Michael Mmoh (USA) 6-4, 6-0
Nick Kyrgios (AUS X3) bt Alexandr Dolgopolov (UKR) 1-6, 6-3, 6-4
Ryan Harrison (USA) bt Denis Istomin (UZB) 7-6 (8/6), 4-2 rtd
Grigor Dimitrov (BUL X1) bt Kyle Edmund (GBR) 6-3, 6-7 (3/7), 6-4
Aliaksandra Sasnovich (BLR) bt Anastasija Sevastova (LAT X7) 7-6 (7/3), 6-4
Elina Svitolina (UKR X3) bt Karolina Pliskova (CZE X2) 7-5, 7-5