France’s Kristina Mladenovic beat former champion Caroline Wozniacki to reach the Indian Wells semi-finals and break into the world’s top 20.
The fast-improving 23-year-old, seeded 28th, saw off 2011 winner and 13th seed Wozniacki 3-6 7-6 (7-4) 6-2.
Mladenovic next faces American Venus Williams or Russia’s Elena Vesnina.
Spain’s Pablo Carreno Busta saved two match points to beat Uruguay’s Pablo Cuevas 6-1 3-6 7-6 (7-4) and become the first man into the semi-finals.
Busta, the 21st seed, will face the winner of the match between Switzerland’s third seed Stan Wawrinka and Austrian eighth seed Dominic Thiem.
Mladenovic added Wozniacki to seven-time Grand Slam champion Venus Williams, world number three Karolina Pliskova and, earlier this week, fourth seed Simona Halep on the list of leading names she has beaten in 2017.
She began her quarter-final slowly, falling 5-1 down against Wozniacki, who was in form herself after recent finals in Doha and Dubai, and had won all three of their previous matches.
But the Frenchwoman showed why her singles game is beginning to match the level that sees her currently ranked third in doubles.
Her more powerful game began to dominate Wozniacki and, after edging the second set in a tie-break, Mladenovic raced way with the decider as the Dane struggled with an ankle problem.
“I was very frustrated with the beginning of the match,” said Mladenovic, who won her first WTA title in St Petersburg earlier this year.
“I was hitting a lot of unforced errors and you can’t do that against a top player like Caroline.
“I felt like I had to adjust to this huge court. It feels different to play out here after hiding out on the small courts. I just tried to stay positive and fight like always.”