The 20-year-old's exit means Serena Williams remains the last woman to successfully defend the US Open title back in 2014.
Coco Gauff survived late-match drama to keep her US Open title defence alive with a 3-6, 6-3, 6-3 victory over Elina Svitolina on Friday.
Gauff, seeded third, fired 10 aces and needed just 66 minutes to beat 66th-ranked Gracheva. She saved eight break points -- including two with aces in the final game
Gauff was not the only big name going out, as Rybakina crashed to a 3-6 7-6(3) 6-4 defeat by former US Open runner-up Leylah Fernandez.
Tearful Coco Gauff was dumped out of the Olympics Games tennis tournament on Tuesday in a stormy defeat to impressive Donna Vekic of Croatia.
The world number one is just one match away from becoming the first woman to win the tournament in three straight years since Justine Henin in 2007 after a 6-2, 6-4 victory.
World number three Coco Gauff came back from a set down to defeat Ons Jabeur and reach her second French Open semi-final on Tuesday.
Gauff has been outspoken from a young age, and grew up with activism engrained in her DNA, passed on from her grandmother Yvonee Lee Odom, who desegregated her high school in Delray Beach in the early 1960s.
Formidable world number two Aryna Sabalenka blasted past Coco Gauff into the Australian Open final on Thursday to keep her title defence on track.
Fourth seed Gauff, attempting to become the first woman to back up a US Open title with a Grand Slam win in Australia since Naomi Osaka in 2018-19, has been almost as impressive.
Fourth seed Gauff said ahead of the opening Grand Slam of the year at Melbourne Park that she wanted to win "multiple" major titles after her breakthrough at Flushing Meadows.
"Some players' goal is to win a Grand Slam. Once they reach that, it's kind of what's next?" Gauf said on Friday
Coco Gauff held her nerve to beat Elina Svitolina in a gruelling three-set final on Sunday to retain her Auckland Classic title in an ideal warm-up for the Australian Open.
Let’s revisit the cream of the crop from a stellar year.
Gauff, 19, produced a gutsy performance on the Arthur Ashe Stadium court to win 2-6, 6-3, 6-2 in 2hr 6min to complete a fairytale transformation in her season's fortunes.
American teenager Coco Gauff shrugged off a 50-minute stoppage caused by climate protesters to power into the US Open final on Thursday with a straight sets defeat of Karolina Muchova.
Djokovic shrugged off ninth seed Fritz 6-1, 6-4, 6-4 to extend his dominance of American players in New York and take another step closer to a record-extending 24th men's Grand Slam title.
Coco Gauff won the final 10 games of her match against Elise Mertens, completing a 3-6, 6-3, 6-0 comeback and reaching the US Open round of 16, where she will face Caroline Wozniacki on Sunday.
Sixth seed Gauff, seen as one of the favourites for the title after recent tournament wins in Washington and Cincinnati, came from behind to win 3-6, 6-2, 6-4 in an attritional 2hr 50min tussle on the Arthur Ashe Stadium.
