Novak Djokovic has suffered an injury scare just days before the start of his US Open defence, which forced him to cut a training session with Holger Rune short on Friday. The Serb is said to have felt some discomfort while practising at Flushing Meadows and was unable to continue after receiving treatment.

Thousands of fans attended the Arthur Ashe Stadium on Friday afternoon to witness the 24-time Grand Slam champion put in some of his final preparations with Rune.

However, after 30 minutes, there was no sign of Djokovic and Rune left the court, not before offering photos and autographs to the disappointed masses.

There was confusion about Djokovic's no-show, considering members of his team and his bags were ready and waiting on the Arthur Ashe court.

But, according to TV2, the 37-year-old picked up an issue while out on a small training court with Rune, who was informed after half an hour of waiting that his partner wouldn't be continuing.

It's claimed that the Norwegian star and Djokovic trained at a very high level for an hour from noon to 1pm local time in New York.

The extent of the four-time US Open winner's injury remains to be seen, but Rune ensured those present during fan week weren't too disappointed by hitting balls out to the crowd before departing.

The report adds that the 21-year-old then continued his practice with a new hitting partner on one of the smaller courts for another hour.

Djokovic lifted his fourth US Open and 24th major crown last year by beating Daniil Medvedev 6-3 7-6 6-3.

He is scheduled to start his 2024 campaign against Moldova's Radu Albot on Tuesday, fresh off winning his maiden Olympic gold medal in Paris this summer, beating Carlos Alcaraz in the final at Roland Garros.

Victory against Albot would set up a second-round clash against Jan-Lennard Struff or Laslo Djere.

Alexei Popyrin will likely be his third-round opponent if both players can avoid any early upsets.

There will also be hope that Djokovic's training niggle doesn't turn into something more serious either before his US Open campaign begins or once he gets going.

Djokovic is a favourite to seal glory in New York, with French Open and Wimbledon champion Alcaraz most hotly tipped to win his second US Open.

Alcaraz starts his campaign against Australia's Li Tu, while No. 1 seed Jannik Sinner faces America's Mackenzie McDonald.