World number two Aryna Sabalenka overpowered Greece's Maria Sakkari 6-2 6-3 to set up a possible Indian Wells final against world number one Iga Swiatek, who plays Elena Rybakina in Friday's other semifinal.
The Australian Open champion was not at her best but maintained her composure even when her old nemesis - the double fault - reared its ugly head on a sunny day in the Southern California desert.
"In the past I lost so many matches like that after a few not super smart mistakes," said Sabalenka.
"I was reminding myself that it is okay to make mistakes. I'm not a robot, I'm a human. I can miss those shots, and probably that's why I was able to keep fighting and keep trying."
After the start of the match was delayed by more than 30 minutes to fix an audio issue related to the electronic line-calling system, Sabalenka cracked an ace out wide to get the match started.
She broke Sakkari for a third time on an errant Sakkari forehand to capture the first set but the Belarusian's frustration began to mount in the second when two double faults gave Sakkari a look at break points at 2-2.
Sabalenka regrouped to hold for 3-2 and broke Sakkari in a lengthy deuce game for a 4-2 advantage she would not relinquish, pouncing on a short return of serve on match point and burying the ball with an emphatic backhand.
First-time Indian Wells finalist Sabalenka will next face either defending champion Swiatek or Wimbledon champion Rybakina for the title on Sunday.
