Image source, Getty Images
Carlos Alcaraz won the US Open in 2022 aged 19
Phil Cartwright
BBC Sport journalist
US Open 2025
Venue: Flushing Meadows, New York Dates: 24 August-7 September
Coverage: Live radio commentaries across 5 Live Sport and BBC Sounds, plus live text commentaries on the BBC Sport website & app
Carlos Alcaraz showed no signs of being affected by a morning start despite being "not an early person" as he sailed into the US Open fourth round with a comfortable straight-set victory over Luciano Darderi.
The 22-year-old Spaniard had won his first two matches of the tournament during the evening sessions on Arthur Ashe Stadium, but opened play on that court at 11:30 local time on Friday.
Italian 32nd seed Darderi, appearing in the third round of a Grand Slam for only the second time, was swept aside 6-2 6-4 6-0 in one hour and 44 minutes.
"I'm not an early person," said Alcaraz. "For me, it's difficult to wake up in the mornings.
"That's one of the good things about today - I woke up early, did the warm-up and played good."
He continued: "I just tried to start awake. Starting at 11:30 is something I'm not used to, so my first goal was to start well, focused, with energy and a good rhythm.
"I started pretty well, pushing him to the limit and trying to play long rallies. I played great tennis and I'm really proud about it."
Alcaraz received treatment to his right knee and quadricep muscle while leading 5-4 in the second set, but he said afterwards that the discomfort soon disappeared and he was "not worried about it".
He said: "I'm feeling good. I asked for the physio because when he broke my serve, on the last point I just felt something that was not working good in the knee.
"After five or six points, it was gone."
After the medical time-out, Alcaraz broke serve in the very next game to move two sets up, before rattling quickly through the third set to complete victory.
Alcaraz won his first Grand Slam title at the US Open as a teenager in 2022 and is aiming to win his second major of the year after retaining his French Open crown in June.
He will return to the top of the world rankings if he matches or betters Jannik Sinner's performance in New York.
His fourth-round opponent will be the unseeded Arthur Rinderknech, who is into the last 16 of a Grand Slam for the first time in his career.
The world number 82 recovered from losing the first set to beat fellow Frenchman Benjamin Bonzi 4-6 6-3 6-3 6-2.
Emotional Shelton forced to retire injured
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Ben Shelton (right) was consoled by Adrian Mannarino after electing to retire before the start of the fifth set
A shoulder injury ended American sixth seed Ben Shelton's hopes of victory at his home Grand Slam.
The 22-year-old led veteran Frenchman Adrian Mannarino by two sets to one on Louis Armstrong Stadium when the issue first appeared to surface early in the fourth set.
After receiving treatment during a medical time-out, Shelton played on but regularly grimaced and grasped his left shoulder after hitting forehands from then on.
His powerful serve did not seem to be affected too much, but he was broken midway through the fourth set and when Mannarino took it 6-4 to level the match, a tearful Shelton chose to retire before the start of the decider.
"When he started to have pain, he was leading and would have probably won the match," said 37-year-old Mannarino, who is through to the last 16 of the US Open for the first time in 15 attempts.
"It's unfortunate for him and very lucky for me. I don't really know what to say - of course I'm happy to get through and I wish him the best."
Mannarino will play Czech 20th seed Jiri Lehecka next, following his straight-set win over Belgium's Raphael Collignon.