MIAMI -- Roberto Bautista Agut didn't take the easiest route to the Miami Open quarterfinals.
The No. 7 seed from Spain fought off a match point before ousting former Miami champion and No. 18 seed John Isner of the U.S. 6-3, 4-6, 7-6 (7) on Tuesday -- his second three-set win in as many matches so far in the tournament.
Bautista Agut lost the first point of the third-set tiebreaker on his serve, giving the big-hitting Isner the early edge. Isner lost the mini-break by putting a forehand into the net five points later, then gave himself match point after a 138 mph ace for a 6-5 edge.
Bautista Agut wasn't fazed, won three of the last four points and escaped.
"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?"
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.
After some early clouds cleared out and bright sunshine starting pounding down, the mid-afternoon temperature reached the mid-80s Fahrenheit at Hard Rock Stadium and the humidity made it feel even hotter.
Medvedev had 11 aces against Tiafoe 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.
Another American man bowed out when No. 32 seed Alexander Bublik of Kazakhstan downed 22nd-seeded Taylor Fritz 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.
"The serve was going well today," Bublik said.
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.