(Photo credit: Geoff Burke-Imagn Images)

World No. 1 Carlos Alcaraz took a surprising defeat to 32nd-seeded American Sebastian Korda, 6-3, 5-7, 6-4 in third-round action of the Miami Open on Sunday in Miami Gardens Fla.

Korda, who was 1-4 all-time against Alcaraz with the win coming in 2022 before the Spaniard won his first grand slam, was sensational on his serve, smashing 12 aces while committing no double faults. He had more winners than Alcaraz (33-30), won more service points (63% to 62%) and saved three of five break points while Alcaraz saved two of five.

'It was a lot of tense moments, for sure. But I think today the ultimate thing was belief, going back to just believing, committing in every shot. Luckily, I got it done at the end,' Korda said in his news conference.

It appeared Korda could be headed for a straight-set win when he led 5-3 in the second set, but Alcaraz won the ensuing four games, including his only breaks of the match, to force a third set.

Korda got the decisive break at 3-3 in the final set and finished off the match in his next two service games.

'(Sebastian) was incredible today,' Alcaraz said. 'Played such a great game. A lot of tight, tight moments that I just didn't make the most of it. I think he was better on those points, on those moments. I would say that was the key of the match.'

Alcaraz, who started the calendar year with 12 straight wins, is 5-2 since and failed to make the Round of 16 at Miami for the second straight year.

Of the eight third-round matches contested Sunday at Hard Rock Stadium, the other seeded competitor to fall was No. 14 Karen Khachanov of Russia, who fell 6-3, 7-6 (2) to Spanish qualifier Martin Landaluce.

Khachanov had more than double as many unforced errors (26) as winners (12), facing eight break points and saving four of them. Landaluce, 20, is through to the fourth round of an ATP Masters 1000 event for the first time. He'll face the 21-year-old Korda next for a spot in the quarterfinals.

Along with Korda, two other seeded Americans took care of business Sunday. No. 6 Taylor Fritz disposed of fellow American Reilly Opelka 6-3, 6-4 in 63 minutes, and No. 22 Tommy Paul outlasted Belgium's Raphael Collignon for a 6-4, 3-6, 7-6 (5) win in 140 minutes.

Czech No. 21 seed Jiri Lehecka (6-3, 7-6 (6) over Ethan Quinn), No. 24 Valentin Vacherot of Poland (7-6 (5), 6-4 over Italy's Matteo Berrettini), French 28th-seed Arthur Fils (6-0, 6-1 over Greece's Stefanos Tsitsipas) and No. 29 Tomas Martin Etcheverry of Argentina (7-5, 6-4 over Spain's Rafael Jodar) each advanced into the fourth round with straight-set victories.

--Field Level Media