Indian Wells: Venus Williams & Simona Halep suffer shock semi-final losses
Naomi Osaka and Daria Kasatkina will contest Sunday's BNP Paribas Open final at Indian Wells after shock semi-final victories over Simona Halep and Venus Williams respectively.
Unseeded Osaka, ranked 44 in the world, thrashed lacklustre world number one Halep 6-3 6-0 in 64 minutes.
Fellow 20-year-old Kasatkina beat world number eight Williams 4-6 6-4 7-5.
It was the Russian's fourth consecutive victory over a current top-20 player, all of whom have won Grand Slams.
World number 19 Kasatkina overcame 2017 US Open champion Sloane Stephens in the third round, before beating January's Australian Open winner and world number two Caroline Wozniacki.
Then, in the last eight, she knocked out world number 10 Angelique Kerber, who won both the Australian and US titles in 2016.
"[After a] match like this, you're just speechless," she said. "Too many emotions and you cannot explain everything. It's one of the best nights in my life, for sure."
Seven-time Grand Slam champion Williams, 37, was winning matches at Indian Wells before Kasatkina had even been born, but was worn down by the youngster, who broke her seven times.
After the pair traded the opening two sets, Williams eked out a 5-4 lead in the third after around two and a half hours of play but the American was left breathing heavily in her chair.
Kasatkina responded, winning the final three games and clinching the win on her second match point after two hours 49 minutes.
"Anyone who gets used to losses should give up on life," said Williams, who beat sister Serena in the third round. "I have to stop making that many errors against her."
Japan's Osaka, meanwhile, has taken her share of big-name scalps in California, knocking out Maria Sharapova, Agnieszka Radwanska, Karolina Pliskova and now Halep.
That astounding win over the Romanian was her fourth career victory over a top-10 player and her second this week after beating world number five Pliskova in the last eight.
"I feel like there is a new generation and we are trying to push through," said Osaka.
Halep had won 18 of her 19 matches this season but the 26-year-old's form collapsed with this semi-final tied at 3-3 in the first set.
She lost the next nine games, with Osaka keeping her composure to save four break points in the final game of the match before clinching victory on her third match point.
"I was kind of nervous because it kept going back and forth," she said. "But I'm really glad I was able to finish on my serve instead of having to break her."
Halep was only able to convert one of her seven break points and coughed up 27 unforced errors as she suffered just her second defeat of the year.
"I just was not ready," she said. "I missed the ball a lot and I didn't play what I had to play. I don't find excuses. She was better."
BBC tennis correspondent Russell Fuller at Indian Wells
Kasatkina's win over Williams was almost certainly the match of the tournament. The 20-year-old mixed power and guile to recover from the loss of the opening set, and is now tantalisingly close to making her top-10 debut.
It continues an extraordinary run of success here at Indian Wells. To reach the final, in consecutive rounds she has beaten Stephens, Wozniacki, Kerber and now Williams - all Grand Slam champions.
And so the final will be contested by two 20-year-olds. Osaka's thrilling potential has burst into the open with wins over Sharapova, Radwanska, Pliskova and now Halep.
This second semi-final was, however, a huge anti-climax. Halep did not win a single game in the second set. It was a curiously lacklustre performance by the world number one.