World tennis No.1 Novak Djokovic has pleaded with his fans to leave a US Open line judge alone after a massive abusive pile-on following his shock disqualification from the tournament.

Djokovic was booted from Flushing Meadows on Monday (Australian time) after accidentally hitting the line judge in the throat with a ball.

She dropped to her knees at the back of the court, and was clearly struggling to breathe, although she was later given the all-clear.

It was a stunning end to Djokovic’s bid for an 18th grand slam title and his 26-0 start to this season. It also cost him $US267,500 ($370,000) in forfeited tournament prize money and various fines for poor sportsmanship.

The Serbian star skipped a post-match media conference ($7500 fine) and left Flushing Meadows quickly. He also apologised to the woman via social media later on Monday.

She was not named by either Djokovic or US Open officials. But a Serbian newspaper has reportedly shared her Instagram handle, sparking an abusive tirade – including death threats – from fans.

On Tuesday, Djokovic followed up with a Twitter plea to his fans to leave the injured line judge alone.

“Please also remember the linesperson that was hit by the ball last night needs our community’s support too,” he wrote.

“She’s done nothing wrong at all. I ask you to stay especially support and caring for her during this time.”

Tweet from @DjokerNole

It came as former tennis “bad boy” John McEnroe said Djokovic would likely have to endure similar labels for the rest of his career after Monday’s incident.

McEnroe, who is no stranger to grand slam defaults, accused Djokovic of making a “rookie mistake”.

He said Djokovic, who has already courted controversy in 2020 by staging an ill-fated tournament amid the coronavirus pandemic and being instrumental in the creation of a controversial new players association, will struggle to live the latest incident down.

“The pressure just got to him, I think,” McEnroe told ESPN.

“A lot’s been going on off the court, it’s obviously affected him and now whether he likes it or not he’s going to be the bad guy for the rest of his career.

“It was a rookie mistake made by him to hit a ball back where he wasn’t even looking where he was hitting it.

“He’s been there and done that, and certainly I know from some experience that you’ve got to be careful out there.”

McEnroe was the first player to be defaulted from a grand slam tournament at the 1990 Australian Open, after a series of code violations during his match against Mikael Pernfors.

-with AAP