Shock upsets, marathon encounters and late nights are nothing new at the US Open, but a handful of notable matches at the year’s final grand slam have put the sport and its packed season schedule under greater scrutiny.

This year’s US Open has seen the last two men’s champions exit in the early rounds on successive nights, the tournament’s longest-ever match, the latest-ever start time for any match and latest-ever finish for a women’s match.

Olympic gold medallist Novak Djokovic said he “felt out of gas” after his US Open title defence ended after three late matches at Arthur Ashe Stadium.

World No. 3 Carlos Alcaraz said physical and mental fatigue contributed to his second-round collapse after securing the Roland Garros and Wimbledon titles and a silver medal run in Paris left him low on energy.

The shock exits, long matches and late nights should serve as a warning that the scheduling of events needs a rethink, the Professional Tennis Players Association (PTPA), a player advocate group that Djokovic co-founded, said.

“There is no question about how spent mentally and physically players are. The Olympics have added to that,” said Romain Rosenberg, PTPA’s deputy executive director.

“The tennis schedule is so tight ... I took a little break after the Olympic Games,” Alcaraz said after his defeat to Botic van de Zandschulp. “Probably it wasn’t enough.”

Djokovic echoed that sentiment after his title defence was cut short by Australian Alexei Popyrin the following night.