World number two Aryna Sabalenka suffered a surprise straight-set defeat as Romania's Sorana Cirstea earned the biggest win of her career to reach the Miami Open semi-finals.
Cirstea, 32, beat the Australian Open champion 6-4 6-4 to record her first win over a top-three ranked opponent.
The unseeded Cirstea will play Petra Kvitova or Ekaterina Alexandrova in her first last four appearance at a WTA Masters 1000 event for nearly 10 years.
"I'm a bit speechless," she admitted.
Speaking in her on-court interview, the world number 74 added: "I came out knowing it would be a really tough match.