World No. 1 Ash Barty of Australia won the final nine points to finish off the seventh-seeded Sabalenka in a three-set women's quarterfinal Tuesday, while men's top-seeded Daniil Medvedev of Russia reached the quarters with a straight-set win over Tiafoe — part of a day where the American men's contingent was pared from four to one, with Sebastian Korda the lone round-of-16 survivor for the U.S.
The 20-year-old Korda stunned fifth-seeded Diego Schwartzman of Argentina 6-3, 4-6, 7-5 for the biggest win of his career to date. And it'll make for an interesting Thursday for the Korda family: he'll be in the Miami quarterfinals that day while his sisters, Jessica and Nelly, will be playing in the first round of the first women's golf major of the year, the ANA Inspiration.
"Sebi is a guy who is going to be special, man," Tiafoe said.
Korda, whose father Petr Korda reached No. 2 in the world during his stellar career, put on a show to delight the evening crowd. He was broken at 5-4 in the third to give Schwartzman hope, then responded by breaking the Argentine right back and finally serving out the match.
By then, it was maybe a bit cooler than the brutal conditions that players endured in the day session — but still tough, which Korda appreciated.
"I love the heat and I love the humidity. The hotter it is, the more humid it is, the happier I am," said Korda, who faces fourth-seeded Andrey Rublev of Russia in the quarterfinals.
Rublev beat Marin Cilic 6-4, 6-4 on Tuesday night.
After some early clouds cleared out and bright sunshine starting pounding down, the mid-afternoon temperature reached the mid-80s Fahrenheit (upper 20s Celsius) at Hard Rock Stadium and the humidity made it feel even hotter.
Barty didn't wilt, ousting Sabalenka 6-4, 6-7 (5), 6-3 for her third three-set win in four matches at the tournament. Medvedev beat Tiafoe 6-4, 6-3, and has gone 10-1 in sets against the American in their past four head-to-head matchups.
"Everywhere in the world there are different conditions and at times it suits you more than other places," Barty said.
"I feel like these are very familiar conditions for me. With the heat and humidity, it's very similar to Brisbane where I grew up and what I was born and bred and trained in my whole life." Barty faced seven break points in the match and saved them all. She'll meet No. 5 seed Elina Svitolina in Thursday's semifinals; Svitolina eased past Anastasija Sevastova 6-3, 6-2 on Tuesday night to make the final four in Miami for the first time.
Barty is now 18-3 in her past 21 three-setters, 10-1 in her past 11 quarterfinal matches and 12-3 in her past 15 meetings against fellow top-10 players. And she ran her winning streak in Miami to 10 matches.
"I enjoy these courts," Barty said.
"You know, I enjoy the balls and how they are responsive to spin. A lot of different elements. But, you know, there are a lot of places around the world that I enjoy playing, and here is one of them." Tiafoe was a quarterfinalist at Miami in 2019 and couldn't repeat that feat, nor John Isner. He wasted a match point during a third-set tiebreak and fell to seventh-seeded Roberto Bautista Agut of Spain 6-3, 4-6, 7-6 (7).
Bautista Agut will face Medvedev in the quarterfinals. Medvedev had 11 aces and showed no signs of wear, two days after cramping in the heat during a third-round win.
"I think we were both really tired, but I think we made an amazing show. I was really happy with my performance today," Medvedev said.
It was Isner's earliest Miami exit since 2017, when he lost in the third round. He won the tournament in 2018 and lost the final in 2019 to Roger Federer in straight sets.
"He makes always difficult matches playing against him," Bautista Agut said. "He has a very big serve and a lot of power from baseline with the forehand. It makes it always difficult, no?" Tiafoe needed a medical timeout in the second set of his match, the heat and humidity taking its toll. He was up a break at the time, and the match simply slipped away from there.
"I felt I couldn't really breathe," Tiafoe said.
"I felt like my heart was beating out of my chest. I was burping a lot, couldn't really settle myself. I burp a lot, haven't discussed it a lot, during these matches, but obviously today it was out of control." No. 22 seed Taylor Fritz of the U.S. also bowed out, falling to No. 32 Alexander Bublik of Kazakhstan 6-7 (5), 6-3, 6-4. Bublik will face No. 21 seed Jannik Sinner of Italy in the quarterfinals; Sinner advanced with a 6-3, 6-2 win over Emil Ruusuvuori of Finland.
No. 26 seed Hubert Hurkacz of Poland pulled off a mild upset, beating No. 12 Milos Raonic of Canada 4-6, 6-3, 7-6 (4). Hurkacz is off to the quarters to face No. 2 seed Stefanos Tsitsipas of Greece, a 6-2, 7-6 (2) winner over No. 24 Lorenzo Sonego of Italy in the final match Tuesday night.
