World reacts in disbelief to Djokovic's default

With no Roger Federer or Rafael Nadal in the draw, it seemed no one could beat the 17-time major champion but himself at this year's US Open. The tennis world was left in utter disbelief.

Disqualifications aren't new in tennis but they are indeed rare. There was John McEnroe in 1990 who was defaulted from his fourth-round bout at the Australian Open after receiving three code violations, as well as Serena Williams similarly going out from the 2009 US Open semifinals. More recently, in 2017, Denis Shapovalov was disqualified from his Davis Cup match after striking a ball that hit umpire Arnaud Gabas directly in his left eye.

On Sunday, Novak Djokovic became a member of the most notable defaults of all time during his round of 16 match against Pablo Carreno Busta. The world No. 1 was frustrated as he walked to the bench after getting broken to go down, 5-6, in the first set. He would pull a ball out of his pocket and slap it towards the back of the court. Although it wasn't struck with as much force as Shapovalov's, it would hit the lineswoman in the throat.

"No, of course I think this was not intentional," Carreno Busta told press (Djokovic did not speak to media). "I don't think that any one of us, of the players, do this kind of thing intentional. It's just the moment. It's just I broke him the serve, and, you know, he throw the ball."

As the lineswoman struggled to find her breath, Djokovic ran towards her to check and make sure she was OK. She would be escorted off the court to receive treatment. Shortly thereafter, USTA officials would make the tough decision to default the No. 1 seed.

With no Roger Federer or Rafael Nadal in the draw, it seemed no one could beat the 17-time major champion but himself at this year's US Open. The tennis world was left in utter disbelief.

Throughout his career Djokovic has struggled to find a strong footing with tennis fans and it seems he could potentially find himself in a tricky spot again with viewers.

"You take that risk and if you do hit someone, you're going to be defaulted," James Blake said during the live broadcast. "He did and it was a very sad and unfortunate situation,"

Djokovic has thrown and hit balls in anger before, including a close call at the Australian Open in 2016, so it felt like it might only be a matter of time before it cost him.

Just a couple of points earlier, Djokovic struck a ball much harder into the court's side wall. Dealing with left shoulder pain from a fall in the same game, it was clear the Serbian was emotional.

According to the USTA's statement, Djokovic might have not had any poor intention, but he did hit the ball with negligent disregard of consequences. As Billie Jean King said in her tweet, "the rule is the rule."

Djokovic skipped press but released a statement, and would come out in defense of the lineswoman who was getting some flack on social media.

Carreno Busta now reaches the US Open quarterfinals where he will face Shapovalov.

Throughout his career Djokovic has struggled to find a strong footing with tennis fans and it seems he could potentially find himself in a tricky spot again with viewers.

"You take that risk and if you do hit someone, you're going to be defaulted," James Blake said during the live broadcast. "He did and it was a very sad and unfortunate situation,"

Djokovic has thrown and hit balls in anger before, including a close call at the Australian Open in 2016, so it felt like it might only be a matter of time before it cost him.

Just a couple of points earlier, Djokovic struck a ball much harder into the court's side wall. Dealing with left shoulder pain from a fall in the same game, it was clear the Serbian was emotional.

According to the USTA's statement, Djokovic might have not had any poor intention, but he did hit the ball with negligent disregard of consequences. As Billie Jean King said in her tweet, "the rule is the rule."

Djokovic skipped press but released a statement, and would come out in defense of the lineswoman who was getting some flack on social media.

Carreno Busta now reaches the US Open quarterfinals where he will face Shapovalov.