Unseeded Romanian Sorana Cirstea earned the biggest win of her career with a 6-4 6-4 victory over world number two Aryna Sabalenka to reach the Miami Open semi-final.
Cirstea, who has yet to drop a set in Miami and is the last unseeded player in the draw, delivered a stunning performance while taking advantage of some untimely double faults to become only the third person to beat Sabalenka this year.
With the win, the 32-year-old Cirstea reached her second WTA 1000 semi-final nearly 10 years after reaching her first.
"I am a bit speechless," said world number 74 Cirstea. "I came out knowing that it was going to be a really tough match.
"Aryna hits so hard, so I knew I had to hold my ground and I am very, very happy with my performance today and it's a bit unexpected to be honest."
Cirstea will face either Czech 15th seed Petra Kvitova or 18th-seeded Russian Ekaterina Alexandrova in the semis.
On the men's side, a two-hour mid-match rain delay could not cool off sizzling Jannik Sinner, who crushed unseeded Finn Emil Ruusuvuori 6-3 6-1 in their one-sided quarter-final.
The 10th-seeded Italian ripped a backhand return winner to capture the first set and rolled from there to improve to a career 5-0 against Ruusuvuori.
"We both played well today but I won the important points," said Sinner.
"It's never easy when you are up and you get interrupted, but I came back and played well."
Rain washed out Wednesday's remaining matches, including a first meeting between world number one and defending champion Carlos Alcaraz and American Taylor Fritz.
That match will be held during the evening session on Thursday, weather permitting.