Defending champion Ashleigh Barty moved into the Miami Open semi-finals with a battling win over Belarusian seventh seed Aryna Sabalenka.
The Australian world number one won 11 of the final 12 points, as Sabalenka struggled with an abdominal injury, to seal a 6-4 6-7 (5-7) 6-3 victory.
Barty, 24, saved all seven of the break points she faced in the match.
"That was the best level I've played for a long time, especially for a sustained period," said Barty.
She is the first player to reach the last four, where she will face Ukrainian fifth seed Elina Svitolina or Latvia's Anastasija Sevastova.
In the men's event, Russian top seed Daniil Medvedev reached the quarter-finals with a 6-4 6-3 win against American opponent Frances Tiafoe.
Medvedev, who rose to world number two earlier this month, faces Spanish seventh seed Roberto Bautista Agut in the last eight.
Second seed Stefanos Tsitsipas also reached the last eight with a 6-2 7-6 (7-2) win over Italian Lorenzo Sonego.
Greek Tsitsipas, who is seeking a first Masters 1000 title, will play Poland's world number 37 Hubert Hurkacz, who beat Milos Raonic in three sets.