Novak Djokovic did not go easy on himself when assessing the listless way he performed from the start of the US Open, pointing to his sloppy serving as the main reason the defense of his 2023 title surprisingly ended in the third round.
"I have played some of the worst tennis I have ever played, honestly," Djokovic said, just after midnight as Friday turned to Saturday. "Serving -- by far -- the worst ever."
With 14 double faults, raising his tournament total to 32, Djokovic bowed out with a 6-4, 6-4, 2-6, 6-4 loss to 28th-seeded Alexei Popyrin of Australia, another shocking result at Flushing Meadows one night after 2022 champion Carlos Alcaraz exited.
It's Djokovic's earliest loss at a major since the 2017 Australian Open, where he lost in the second round to Denis Istomin. It's also only the third time in the Open era that two of the top three men's seeds at the US Open are gone before the fourth round; the other instances were in 1973 and 2000.
"It was just an awful match for me," the No. 2-seeded Djokovic said. "I wasn't playing even close to my best. It's not good to be in that kind of state where you feel OK physically, and of course you're motivated because it's a Grand Slam, but you just are not able to find your game. That's it. The game is falling apart, and I guess you have to accept that tournaments like this happen."
Not often for him, though.
After all, Djokovic was trying to become the first player in tennis history with 25 Grand Slam singles titles. Instead, after knee surgery in June, he finishes a year without claiming at least one major championship for the first time since 2017. Before that, it hadn't happened since 2010.
Also of note: It's the first season since 2002 in which none of the Big Three of men's tennis -- Djokovic, Rafael Nadal and Roger Federer -- earned a Slam trophy.
The third-round exit equals Djokovic's worst showing at Flushing Meadows; the only other occasions he was defeated that early at the US Open came in 2005 and 2006. The man who defeated Djokovic 18 years ago, International Tennis Hall of Fame member Lleyton Hewitt, is now Australia's Davis Cup captain and was sitting in Popyrin's guest box at Arthur Ashe Stadium.
Djokovic, Popyrin said, "wasn't playing his best tennis; I was waiting for him to kind of step up."
"I didn't want to be one of those moments where Novak kind of stepped up and came back from two-sets-to-love down," Popyrin said. "That was going through my head."
Djokovic, who is 37, has reached the final at Ashe 10 times, leaving with the title in 2011, 2015, 2018 and 2023.
On Friday, though, he was sluggish and emotionally flat, perhaps residual fatigue after collecting his first Olympic gold medal for Serbia by beating Alcaraz in the final at the Paris Games earlier in August.
"Obviously, it had an effect," Djokovic said. "I spent a lot of energy winning the gold, and I did arrive to New York just not feeling fresh mentally and physically. But because it's the US Open, I gave it a shot and I tried my best. I mean, I didn't have any physical issues. I just felt out of gas. And you could see that with the way I played."
The No. 3-seeded Alcaraz entered the US Open as the tournament favorite having won the French Open and Wimbledon. He also acknowledged his energy was lower than he realized after being eliminated by 74th-ranked Botic van de Zandschulp 6-1, 7-5, 6-4 on Thursday night.
"I woke up this morning and showed my girlfriend straightaway, in shock. It was crazy. Results like that happen," said Popyrin, who had never set foot on the playing surface in 23,000-plus capacity Ashe until about 20 minutes before taking on Djokovic. "I thought to myself: Why not me today?"
Djokovic replaced Alcaraz as the money-line pick to take the men's title, according to ESPN BET, but that status didn't last long. Now the only past US Open men's champion remaining before Week 1 is even over is Daniil Medvedev, whose lone Slam title came in 2021. He plays No. 31-ranked Flavio Cobolli on Saturday in the third round.
For the 25-year-old Popyrin, the victory represented a breakthrough: He had been 0-3 against Djokovic and 0-6 in third-round matches at majors.
But the strong-serving Popyrin is playing as well as ever, coming off the biggest title of his career less than three weeks ago at a hard-court tournament in Montreal, where he picked up five wins against opponents ranked in the top 20.
Everything was working against Djokovic.
Popyrin was terrific at the net, going 10-for-10 on serve-and-volley approaches and 25-for-36 overall on points when he pushed forward. Djokovic, in contrast, won the point on only 19 of his 40 trips to the net, in part because Popyrin kept flipping passing shots by him.
Popyrin took big cuts with his powerful forehand, accumulating 22 of his 50 total winners with the shot.
And he broke Djokovic five times, including for a lead of 3-2 in the fourth. That game felt titanic, lasting more than 10 minutes. It included four break chances for Popyrin, who converted the last one with an inside-out forehand to close a 22-stroke exchange then rocked back on his heels, clenched both fists and let out a roar. He took Djokovic's next service game too to make it 5-2.
The first time Popyrin served for the match, he faltered, allowing Djokovic to break. The second time, Popyrin finished the deal, holding at love when Djokovic sent a forehand long.
Now Popyrin will try to reach his first Grand Slam quarterfinal by getting past No. 20 Frances Tiafoe, who advanced Friday with a 4-6, 7-5, 6-7 (5), 6-4, 6-3 win over No. 13 Ben Shelton in a matchup of two Americans.
"If he serves well, plays well, he can beat anybody," Djokovic said about Popyrin. "Look, Alcaraz is out. I'm out. Some big upsets. The draw is opening up."
The Associated Press contributed to this report.