The 2024 U.S. Open will be one Coco Gauff would like to forget sooner rather than later.

The defending champion failed to advance past the Round of 16 on Sunday afternoon, losing to fellow American Emma Navarro, 6-3, 4-6, 6-3.

Navarro took care of business in the first set, and the second was a back-and-forth battle early. With the set tied at three, Navarro broke Gauff’s serve to go up 4-3, putting Gauff on thin ice.

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Coco Gauff upset

Coco Gauff is shown after a miss during her match against Emma Navarro at the U.S. Open. (Robert Deutsch-USA TODAY Sports)

But it wasn’t thin enough as Gauff returned the favor by breaking Navarro’s serve. Gauff then took a 5-4 lead and then broke Navarro again to take the match to a third set.

Gauff won the first game, with all signs pointing to momentum on her side. But it didn't carry over as Navarro took the next three. The two then alternated games, putting Navarro up 5-3 with Gauff serving, but that wasn’t much of an advantage for the reigning champ, who double-faulted three times to help Navarro advance to the quarterfinals.

Coco sad

Coco Gauff is shown after a miss during her match against Emma Navarro at the U.S. Open. (Robert Deutsch-USA TODAY Sports)

NOVAK DJOKOVIC'S SHOCKING US OPEN LOSS ENDS INCREDIBLE 22-YEAR STREAK

Gauff had 19 double faults in the match, 11 of which came in the final set. After her final one, she threw her racket down in anger.

It's the second grand slam in a row she lost in the Round of 16 after advancing to at least the semifinal in her previous three. It's also the sixth year in a row the reigning champ failed to make it to the quarterfinals. No reigning champ has made it to a semifinal since Serena Williams in 2015.

Navarro next faces Paula Badosa of Spain on Tuesday; it's her second straight quarterfinal in what's been a career-year for the 23-year-old, who had never made it past the second round of a grand slam until this year.

Coco and Emma hugging

Emma Navarro, left, is shown after beating Coco Gauff at the 2024 U.S. Open. (Robert Deutsch-USA TODAY Sports)

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She's advanced to at least the Round of 16 in each grand slam this year, with her best finish being the quarterfinal in July's Wimbledon.

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