Dubai - Top seed Simona Halep had to come from behind for a second straight day on Thursday, overhauling Aryna Sabalenka 3-6, 6-2, 6-2 to reach the Dubai Championships semi-finals.
Halep, who had saved a match point in knocking out Ons Jabeur 24 hours earlier, said she had to pick up her pace after losing the first set.
"Everything was a little bit fast, too powerful. When I got the rhythm, it was much easier for me to feel the game," said the world number two.
"I played quicker in the second and third set. She didn't have time to hit the ball. I think that was the key of the match.
"It's good to have tough matches. I'm here to give everything I have to win every match I play. I'm happy with these matches."
The Romanian star will face Jennifer Brady on Friday for a place in the final.
US qualifier Brady, who beat third seed Elina Svitolina in the first round, booked her last-four spot by dispatching ninth seed Garbine Muguruza, 6-7 (5/7), 6-3, 6-4.
Elena Rybakina claimed a season-leading 18th victory with a 7-6 (7/1) 6-3 win over second seed Karolina Pliskova of the Czech Republic.
The Kazakh winner has been on a tear in 2020, winning the Hobart trophy and playing finals in Shenzhen and last weekend in St Petersburg.
Rybakina will Friday face Petra Martic after the Croatian eighth seed defeated Anett Kontaveit of Estonia 7-6 (7/4), 6-1.
As she had on Wednesday, when playing Tunisian wildcard Jabeur, Halep had to fight her way out of a deficit after losing the opening set.
The 2015 Dubai champion lifted her game to win the second set and ran off to a 4-1 lead in the final set before finishing off the night three games later.
Victory avenged the loss Halep suffered against Sabalenka last month in Adelaide.
Brady, who ranks just outside the Top 50, has stunned herself with her form this week.
"I was able to find a way, I wasn't feeling my best," she said after seeing off Muguruza.
"Maybe I didn't play my best tennis, but I stayed in there, competed and came out on top."
Brady recovered from a set down against the two-time Grand Slam winner from Spain, winning the second set by breaking her opponent's last two serves.
She finished off the upset a set later on a second match point.
"I had so many opportunities, I can't count how many I had. They didn't go my way," said Australian Open runner-up Muguruza who converted on only one of 10 break points.
"Every time I had an opportunity, she was playing the point well, serving big, making winners."
Simona Halep (ROU x1) bt Aryna Sabalenka (BLR x7) 3-6, 6-2, 6-2
Elena Rybakina (KAZ) bt Karolina Pliskova (CZE x2) 7-6 (7/1), 6-3