Novak Djokovic urged his fans to be “supportive and caring” of the line judge at the centre of his US Open default row after she was attacked by online trolls.

Djokovic said the official, who was hit in the throat by a ball bashed away in anger by the world number one, had “done nothing wrong at all”.

Some critics on social media accused the line judge while there have been reports of fans targetting her Instagram account with abusive messages.

Djokovic was dramatically disqualified from the US Open on Sunday after accidentally striking a female lines judge with a ball in frustration during his last-16 match, sending shock waves through the tournament.

The world No 1 apologized for hitting the ball in disgust after losing his serve to go 6-5 down in the first set to Spain’s 20th seed Pablo Carreno Busta inside Arthur Ashe Stadium.

Djokovic appeared to be looking the other way when he pulled the ball from his pocket and smacked it in the direction of the official, hitting her full toss in the throat.

The official cried out and began gasping for air as she fell on the turf.

Djokovic rushed over to check on her, placing his hand on her back as she struggled to breathe. After a few minutes she got up and walked off the court looking dazed.

Around ten minutes of discussions then ensued between Djokovic and the tournament referee Soeren Friemel, during which the Serb pleaded his case. He was then declared to have defaulted from the match.

It should have ended there. Most experts agreed that it was the right decision and the US Open officials had gone by the rule book. But the decision was a tough one for Djokovic fans to swallow and many of them started going after the lines judge on social media.

The polite ones were calling her ‘Federer’s agent’ and others were much worse.

Trolls also flooded her Instagram photos with horrible comments, with some of them even referencing the line judge’s late son.

The line judge has now reportedly deleted her social media accounts.

On Tuesday, Djokovic has also taken to Twitter, asking his fans to support the lines judge who has done nothing wrong.

“Dear #NoleFam thank you for your positive messages.. Please also remember the linesperson that was hit by the ball last night needs our community’s support too. She’s done nothing wrong at all. I ask you to stay especially supportive and caring to her during this time. From these moments, we grow stronger and we rise above. Sharing love with everyone. Europe here I come.”

— via Novak Djokovic / Twitter

Djokovic’s show of support is welcome but whether his fans oblige remains to be seen.

In recent years, we’ve seen the ugly side of superstar fandom surface on social media innumerable times. And it seems to be especially prevalent between the #NoleFam and fans of Rafael Nadal and Roger Federer.

Djokovic was disqualified because of the incident as he missed the chance to win his 18th Grand Slam title and close the gap on Rafael Nadal (19) and Roger Federer (20).

He later said he was “extremely sorry” for causing the accident and said he had apologised to US Open organisers for his “behaviour”.

(With AFP inputs)