Carlos Alcaraz has called on tennis chiefs to end late matches at Grand Slams after his record-breaking US Open exit in the middle of the night.
Alcaraz's reign as US Open champion was shattered by Ben Shelton in a five-set thriller that finished at 3.33am local time in New York.
The quarter-final started on a Tuesday evening and finally came to a conclusion after four hours and 28 minutes on a Wednesday morning in the latest finish in US Open history.
The cut-off for matches at Wimbledon is 11pm local time, but the US Open, French Open and Australian Open do not have an alloted time to halt play.
Novak Djokovic's 2024 win against Lorenzo Musetti ended at 3.07am in Paris, with matches in New York and Melbourne often stretching late into the night.
Many leading players have bemoaned the brutal schedule and Alcaraz, a seven-time Grand Slam winner, insists the time has come to make a change at the four majors.
"For an athlete finishing at 3.30 in the morning, it means we had to leave the courts at 4.30, then back to the hotel," he told reporters in London on the eve of this week's Laver Cup.
"You don't go to bed until 6.30 or 7 in the morning. To recover for the next match, the person you play has an advantage.
"It is too much. They are going to have to do something. I'm not saying 3.30 but (even) finishing at 12 is too late already."
Alcaraz was left physically and mentally spent after the gruelling loss to Shelton, which came in his first tournament after over four months out with a wrist injury.
The 23-year-old believes matches that last late into the night are damaging for players and hinder the sport because many fans have to leave the stadium, while the television audience also drops.
"100 percent. It is a shame a match like this didn't reach a lot of people because they have to go to bed, they have to work in the morning," the world number three said.
"If that match had started at 7 or 8pm, at the maximum finishing at 11, the stadium would have been packed. A lot had to miss it because of the schedule."
One way to reduce the number of late matches would be to cut Grand Slam contests from the current best-of-five sets format to the three-set system used elsewhere on the ATP and WTA Tours.
Djokovic, a 24-time Grand Slam champion, recently proposed slashing sets from the first to win six games to the first to win four to reduce match length.
But American legend Andre Agassi insists players who achieve Grand Slam glory are admired for pushing their body to the limits.
Agassi, who won eight majors in his iconic career, said: "I absolutely believe we should have it (five sets). I believe it's possible to get lucky and win two out of three. I don't think you can get lucky and win three out of five.
"I think you really have to earn it. There should be a delineation between winning the Slams, the biggest tournaments, versus other weeks of the year."
Agassi, serving as Team World captain in the latest edition of the Laver Cup, believes cutting back on the length of matches would do a disservice to the history of the sport.
"You don't want it going that late. It's unfortunate. I have been in that position plenty of times," he said.
"But the last thing you want to have is an asterisk next to the history of our sport. You don't want somebody just getting hot for an hour and a half and going through some tough matches.
"We are doing what we can but it is still gladiator stuff. I like it."