Swiss 19th seed Timea Bacsinszky reached the Miami Open semi-finals for the first time in her career after rallying to beat Simona Halep in three sets.
A day after eliminating third seed Agnieszka Radwanska, Bacsinszky continued her giant-killing run by seeing off the fifth-seeded Halep 4-6 6-3 6-2 on Tuesday.
Bacsinszky had never previously contested a final-four clash at Key Biscayne, but she now faces a showdown with Svetlana Kuznetsova.
Kuznetsova outlasted fellow seed Ekaterina Makarova in an all-Russian affair, which finished after midnight local time in Miami.
HALEP JOINS THE CASUALTIES AS BACSINSZKY REIGNS SUPREME
World number one and eight-time champion Serena Williams, as well as Radwanska, farewelled the WTA Premier tournament on Monday and Halep joined the pair through the exit doors 24 hours later.
Everything looked on track for Halep, who broke twice to take out the opening set.
But it all fell away from that point as Bacsinszky rallied to send the Romanian packing.
Bacsinszky, who broke for a 3-1 lead in the second set, eased through the first four games of the final set before serving out the shock result with her 20th winner of the match, which lasted two hours, 28 minutes.
Halep's exit means Angelique Kerber is the only remaining top-10 player in the draw.
KUZNETSOVA EYEING RETURN TO TOP 10
Kuznetsova - the 15th seed - is two wins away from a top-10 comeback after prevailing in a three-set marathon against Makarova.
The former world number two, who stunned Williams in the fourth round, battled to a 6-7 (3-7) 6-4 6-3 triumph in two hours, 44 minutes.
Kuznetsova's gritty victory means she could now return to the top 10 for the first time since 2010 if she lifts the trophy.
GUT IS BACSINSZKY'S GOOD LUCK CHARM
Swiss skier Lara Gut extended her vacation to continue watching friend Bacsinszky and it worked wonders. "She's still here! The Swiss are super happy about it; it was even in the news," Bacsinszky said, then addressing Gut, "Thanks so much for your support; you're also a huge inspiration for me."
KERBER, AZARENKA LOOK TO TEE UP SEMI-FINAL SHOWDOWN
World number three and second seed Angelique Kerber headlines the quarter-final action on Wednesday. The Australian Open champion faces 22nd seed Madison Keys in the evening session. BNP Paribas Open winner Victoria Azarenka will be next up should the Belarusian see off Johanna Konta in the afternoon.