WASHINGTON - The fifth day of the US Open delivered a major upset as No 2 seed Novak Djokovic was eliminated in the third round by Australia's Alexei Popyrin. Meanwhile, Chinese players Zheng Qinwen and Wang Yafan continued their impressive run, advancing to the round of 16.

Djokovic, a 24-time Grand Slam champion, lost to the 25-year-old Popyrin 4-6, 4-6, 6-2, 4-6 on Friday, marking his earliest US Open exit since 2006.

"Congratulations to him and his team. He definitely played better and deserved to win today," said Djokovic, who made 14 double faults in the match, his most ever at a major.

"I have played some of the worst tennis I have ever played, honestly, serving by far the worst ever."

"I didn't have any physical issues. I just felt out of gas, and you could see that with the way I played. Just from the very beginning, from the first match, I just didn't find myself at all on this court," added the Serbian star.

On the women's side, China's ace Zheng faced Germany's Jule Niemeier, a player she had beaten only once in their three previous encounters. While on Friday, it only took Zheng one hour and 21 minutes to secure a commanding 6-2, 6-1 victory.

Zheng dominated the match with an 84 percent first-serve win rate and converted five break points, while Niemeier managed just 47 percent and failed to break Zheng's serve.

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"I remember that match so clearly. In 2022, I lost that match to her at midnight, because that match was really painful. I sat one hour in the US Open at three o'clock and cried by myself alone," said Zheng, reflecting on her previous loss to Niemeier.

"So today, when I played against her since the beginning, I'm really focused because I don't want that feeling to happen to me again. I'm glad I'm the winner today, so I don't have to cry," said the Chinese 21-year-old.

Zheng is going to face the No 24 seed Donna Vekic, her old rival from the Paris Olympics final, where Zheng won in straight sets to claim China's first Olympic singles gold.

"For me, it's just another match to go. It doesn't matter who I play against," Zheng noted. "But of course, in the Olympic Games, I fight a lot. I mean, I almost give everything Olympic Games, but ... playing the US Open. I'm also going to give everything I (have) because I also consider the US Open really, really important for me because Slams is always my dream."

Elsewhere, China's Wang took on three-time US Open finalist Victoria Azarenka. Wang capitalized on Azarenka's 32 unforced errors, nearly twice as many as her own, and converted six break points to win 6-4, 3-6, 6-1, reaching the round of 16 at a Grand Slam for the first time in her career.

China's Shang Juncheng, however, could not maintain his early momentum against eighth-seeded Casper Ruud of Norway. After winning the first two sets, Shang was unable to lead the match, ultimately falling in five sets and exiting in the third round.

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In the other significant match of the day, fourth-seeded Alexander Zverev battled through four sets to defeat Argentina's Tomas Etcheverry, and Belarusian ace Aryna Sabalenka rebounded from a 2-6 first-set loss to win 6-1, 6-2, securing her place in the next round.