Novak Djokovic's time at the 2020 U.S. Open is over.
The top seed in the men's singles draw was defaulted from his fourth-round match with Pablo Carreno Busta after he struck a line judge with a ball.
Djokovic was frustrated after losing a point and struck the ball in the direction of the official, who appeared to be hit near the throat.
After a long conversation with the officials, the 33-year-old was defaulted from the match and the tournament, leaving the men's singles draw with no previous Grand Slam champions.
Alexander Zverev is one of the players who could take advantage of Djokovic's unexpected exit. The No. 5 seed cruised into the quarterfinals via a straight-sets victory Sunday at the USTA National Tennis Center.
Jennifer Brady and Yulia Putintseva clinched victories Sunday to earn the first two positions in the women's quarterfinals. Naomi Osaka will try to join them with a victory Sunday night inside Arthur Ashe Stadium.
Top Men's Results
No. 20 Pablo Carreno Busta def. No. 1 Novak Djokovic, 6-5 (default)
No. 5 Alexander Zverev def. Alejandro Davidovich Fokina, 6-2, 6-2, 6-1
Djokovic was disqualified from the match after losing his temper following a break by Carreno Busta.
Minutes before the action that cost the Serb his U.S. Open title bid, he slammed a ball in frustration into the side wall at Ashe Stadium.
Djokovic turned away from the net, hit the ball in frustration and it unfortunately hit a line judge behind his side of the court.
The tournament officials discussed the punishment for the world No. 1 by themselves and then with the player before the final decision was made.
Carreno Busta is now heading for his second U.S. Open quarterfinal. In 2017, he advanced to the semifinals before falling to Kevin Anderson.
Zverev could be the biggest beneficiary of Djokovic's exit since he was on a collision course to play the top seed in the semifinals.
The fifth-seeded German only allowed Alejandro Davidovich Fokina to win five games over three sets Sunday afternoon. He won 75 percent of his first-serve points, hit 18 aces and produced 39 winners in his three-set triumph.
The winner of Sunday night's match between No. 27 Borna Coric and Jordan Thompson will face Zverev in the final eight.
Top Women's Results
No. 23 Yulia Putintseva def. No. 8 Petra Martic, 6-3, 2-6, 6-4
No. 28 Jennifer Brady def. No. 17 Angelique Kerber, 6-1, 6-4
Brady extended her dominant run in New York into the fourth round, where she defeated one of the six Grand Slam champions to make the final 16 of the women's draw.
The 28th-seeded American produced an immaculate first set against Angelique Kerber in which she lost a single game.
Brady went 2-for-2 on break points, won 75 percent of her first-serve points and cleaned up with seven of eight victories on her second serve in the opening frame.
Kerber produced a better second set, but she was unable to match the level of Brady, who advanced to her first Grand Slam quarterfinal.
Putintseva needed three sets to defeat Petra Martic and land her third Grand Slam quarterfinal berth. The previous two occurred at the French Open.
The No. 23 seed opened with a set victory, but Martic leveled the contest through a second-set win. However, the 25-year-old Kazakh closed out the win with a 6-4 third-set triumph.
Putintseva won despite earning 14 fewer winners and losing more first-serve points than Martic.
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Statistics obtained from USOpen.org.