The last remaining American woman fell in the quarterfinals of the BNP Paribas Open when Venus Williams lost Thursday.
Williams, seeded 12th, came up short against 14th-seeded Russian Elena Vesnina, who scored a 6-2, 4-6, 6-3 victory at Indian Wells, Calif.
Vesnina's semifinal opponent will be No. 28 seed Kristina Mladenovic of France, who came from behind to beat 13th-seeded Caroline Wozniacki of Denmark 3-6, 7-6 (4), 6-2.
The other semifinal match features third-seeded Karolina Pliskova of the Czech Republic and eighth-seeded Svetlana Kuznetsova of Russia.
Vesnina continued the best run of her career in a WTA Tour Premier Mandatory event.
"I'm in the semifinal of BNP Indian Wells tournament, one of the biggest tournaments. I guess I'm on fire," Vesnina said. "I'm enjoying myself on the court, and I'm really happy with my wins here.
"This win today against Venus really means a lot for me. It's never easy to play against her. She's a great champion and always fighting till the end. I'm really happy that I pulled it out."
Vesnina ended Williams' run in the tournament in a two-hour, 11-minute match.
Vesnina ousted No. 2 seed Angelique Kerber to set up the match against Williams, who was bidding for her first title in the event.
"It was not easy," Vesnina said. "When she won the second set, I was thinking how I'd seen previous matches where she was down with match point or set point, and I was like, 'Uh oh, it's happening again. I'm going to be another victim of Venus. I don't want that. I want to win this. I want this match.'"
Instead, Vesnina rallied to set up a match against Mladenovic.
"Kiki is having a great season. She's on fire," Vesnina said. "She can come in to the net. She's using the drop shots, slices, so it's going to be difficult match, but on the other hand, it's very exciting to play the semifinal match here in Indian Wells."
With her win, Mladenovic guaranteed she will reach the top 20 for the first time in her career when the new rankings come out next week.
"It's been a lot of matches and, to be honest, it's like the longest kind of string of winning matches I had so far in my career," Mladenovic said. "It feels great, but in the same time, every day I go out there on the court or in the gym practicing, it's for moment like that.
"So I'm not getting too excited. I'm just super satisfied that I am on that kind of stages right now and trying to use my chances and the opportunities I have."
Mladenovic had never beaten Wozniacki in three previous encounters.
"Caroline is a top player, former World No. 1," Mladenovic said. "She's also in very great shape; she had a very good start of the season, as well, and won lots of matches."
Mladenovic fell behind 5-1 in the first set, failing to convert any of her seven break-point opportunities.
After losing the first set 6-3, Mladenovic led 5-3 in the second set, before Wozniacki forced a tiebreaker. Mladenovic won the first two points in the breaker and never trailed to even the match.
"I was just fighting mentally to be close with her at the scoreboard, and eventually I got my chances," she said. "And I think I played really well in the tiebreak."