The 17-year-old Andreeva, seeded ninth, will face top-seeded Aryna Sabalenka, who avenged her Australian Open final defeat to Madison Keys in ruthless fashion by thrashing the fifth-seed 6-0 6-1.
After a tight first set, the 17-year-old Andreeva was flawless in the tiebreak, leaning over and letting out a roar when she enticed a forehand error from Swiatek on set point.
The Polish second seed stormed back in the second set, breaking in the first game and leveling the contest when Andreeva's backhand went wide.
Andreeva, who was studying handwritten notes during the changeovers, grabbed the momentum back by breaking to open the third set as temperatures in the California desert plummeted and the wind picked up.
She ripped a forehand winner to go up 3-1 as the frustration began to take build for Swiatek, who dumped a backhand into the net on match point.
"After she literally killed me in the second set I thought, okay, I'll just try to fight," Andreeva said on court.
"There is not much I could do about it, she was playing amazing. I just decided to fight for every point.
"It doesn't matter how I put the ball in but I have to put it in. In the end it wasn't too bad."
The ninth seed is coached by former Wimbledon champion Conchita Martinez, who reached the Indian Wells finals twice during her playing days.
"I know that my coach lost in the finals so I'm going to try to be better than her," said Andreeva with a laugh.
Andreeva ran her tour winning streak to 11 matches and ended Swiatek's 10-match run here as the five-time major champion tried to become the first woman to win the tournament in the Southern California desert three times.
The Russian won her first WTA Tour title last month in Dubai to become the youngest player to win a WTA 1000 event. She is now trying to go back to back.
Kim Clijsters also was 17 in 2001 when she lost to Serena Williams in the final.
Swiatek, also the 2002 Indian Wells champion, was seeded second.
Keys, meanwhile, never looked like repeating her Australian Open victory in January.
Sabalenka needed just 51 minutes to complete the win, Keys holding serve late in the second set to avoid a whitewash.
"I wish I would play like that in Australia," said Sabalenka, who admitted she had needed time to recover from that defeat and was looking forward to taking on Andreeva.
"It feels like an old mama playing against a kid. Oh my God, I'm nine years older than her."
with Reuters
