• The defending champion won eight consecutive games en route to a comprehensive victory in California.
• Swiatek will face Wimbledon champion Elena Rybakina on Friday.
World number one Iga Swiatek continued her pursuit of back-to-back Indian Wells titles as she cruised past Romania's Sorana Cirstea in straight sets to reach the semi-finals.
The 21-year-old beat Cirstea, ranked 83 in the world, 6-2 6-3.
The defending champion won eight consecutive games en route to a comprehensive victory in California.
Winner of the French and US Opens last year, Swiatek will face Wimbledon champion Elena Rybakina on Friday.
Kazakhstan's Rybakina, who beat the Czech Republic's Karlina Muchova 7-6 (7-4) 2-6 6-4 in her quarter-final, knocked Swiatek out of the Australian Open in January.
Swiatek, who beat Brito Emma Raducanu in the fourth round, is looking to become just the second woman, after Martina Navratilova in 1990 and 1991, to win back-to-back titles at this tournament.
Cirstea recovered an early break and batted off a break point to level the opening set at 2-2 before Swiatek steamed through the next eight games.
Swiatek powered to two breaks of serve early in the second set before Cirstea clawed one back then held for 4-2, but the top seed is yet to lose a set at the tournament and sailed to a comfortable victory in one hour 22 minutes.
Earlier on Thursday, Rybakina started slowly against Muchova, failing to convert five break points in the first set but eventually forcing a tie-brea, which she won after the 26-year-old's double fault.
World number 76 Muchova deservedly took the second set before Rybakina produced some powerful serves to secure the victory and progress to her first ever Indian Wells semi-final.
Meanwhile, Greece's Maria Sakkari rallied from a set and a break down to beat Petra Kvitova 4-6 7-5 6-1 to secure a second consecutive Indian Wells semi-final spot.
Kvitova started well - having secured a dramatic match-point saving win over Jessica Pegula a day earlier - to take the first set and immediately break Sakkari in the second.
But Sakkari came from 40-0 down in the final game to force a deciding set, which she won in dominant fashion.
The 27-year-old will now face world number two Aryna Sabalenka, who moved into the semi-finals with a 6-4 6-0 victory over American Coco Gauff on Wednesday.