Tennis star Novak Djokovic is getting some tough love after an accidental ball flub got him tossed from the U.S. Open.

Fellow tennis great John McEnroe said Sunday that the Serbian pro would "be the bad guy the rest of his career" after he accidentally hit a line judge with a tennis ball Sunday in a stunning turn of events that saw him disqualified from the tournament in just his fourth-round match.

"The pressure just got to him, I think," McEnroe said on ESPN. "I think 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 the rest of his career. It’ll be interesting to see how he handles it."

2020 US OPEN: WHAT TO KNOW ABOUT MEN'S SINGLES TOURNAMENT

The accident was "obviously not intentioned," McEnroe added, saying he understands the "rules state you gotta treat everyone the same."

NOVAK DJOKOVIC'S DISQUALIFICATION STIRS DEBATE ONLINE

“I didn’t say he couldn’t recover. If he embraces that role, I think he could recover, absolutely," McEnroe -- known himself for getting mouthy with tennis officials throughout his career -- said. "He’s chasing history, he’s trying to pass Rafa [Nadal] and Roger [Federer], we all know that, he’s younger."

"He’s got a lot of things going for him, obviously, but this is obviously a stain that he’s not going to be able to erase, whether he likes it or not. … It’s emotionally how he’s going to handle it. It’s not about the physical part and him getting older," he added.

Novak Djokovic checks a linesman after hitting her with a ball in reaction to losing a point during the fourth round of the US Open tennis championships on Sunday, Sept. 6, 2020, in New York. Djokovic defaulted the match. (AP Photo/Seth Wenig)

Novak Djokovic checks a linesman after hitting her with a ball in reaction to losing a point during the fourth round of the US Open tennis championships on Sunday, Sept. 6, 2020, in New York. Djokovic defaulted the match. (AP Photo/Seth Wenig)

The accident stunted Djokovic's bid for an 18th Grand Slam title. He had come into the tournament the overwhelming favorite, having a 26-0 start to this season.

As he went to change over after a game against his opponent, Pablo Carreno Bust, Djokovic -- after he had just dropped his serve -- hit a ball behind him, a common move for players who have just finished a game during which they served.

CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COM

However, this ball hit a line judge, who could be seen on video falling to her knees in Arthur Ashe Stadium and reaching for her neck.

An on-court discussion with officials ensued, including tournament referee Soeren Friemel. Chair umpire Aurelie Tourte then announced the default, shocking the tennis world and throwing an unexpected twist into the tournament.

The U.S. Tennis Association said in a statement that Djokovic was "defaulted" due to his actions, and that he would lose "all ranking points earned" at the tournament, as well as "be fined the prize money won at the tournament in addition to any or all fines levied with respect to the offending incident."

In the past, players who have hit balls out of anger or frustration and accidentally hit a line judge or ball person have been ousted from tournaments.

NOVAK DJOKOVIC'S US OPEN MELTDOWN COSTS MILLIONS IN PRIZE MONEY, WITH MORE POTENTIAL FINES AHEAD

In an Instagram post Sunday, Djokovic apologized and said the situation has left him "really sad and empty."

"I checked on the lines person and the tournament told me that thank God she is feeling ok [sic]," he wrote. "I‘m extremely sorry to have caused her such stress. So unintended. So wrong. I’m not disclosing her name to respect her privacy."

GET THE FOX NEWS APP

"As for the disqualification, I need to go back within and work on my disappointment and turn this all into a lesson for my growth and evolution as a player and human being. I apologize to the @usopen tournament and everyone associated for my behavior," he said, adding: "I’m very grateful to my team and family for being my rock support, and my fans for always being there with me."

"Thank you and I’m so sorry."

The Associated Press contributed to this report.