Michael Phelps, Naomi Osaka, Karlie Kloss, and other celebrities grace US Open on Day 10, ft. Carlos Alcaraz and Alexander Zverev

The 2023 US Open continues to be a star-studded affair as celebrities from various backgrounds were spotted at the USTA Billie Jean King National Tennis Center on Day 10 (September 6).

Among the high-profile stars who watched the quarterfinal day in New York were swimming legend and most decorated Olympian of all time, Michael Phelps, two-time US Open champion Naomi Osaka, fashion model Karlie Kloss, actors Jason Biggs and Zach Braff, Grammy-winning musician Jon Batiste, billionaire and former New York City Mayor Michael Bloomberg, and more.

Day 10 at the Arthur Ashe Stadium featured the remaining quarterfinal matches in men's and women's singles draws. The day began with women's No. 2 seed Aryna Sabalenka sweeping aside Qinwen Zheng. Then 2021 winner Daniil Medvedev bettered Andrey Rublev in an all-Russian affair.

The third match saw former finalist Madison Keys down reigning Wimbledon champion Marketa Vondrousova before defending men's champion Carlos Alcaraz wrapped up the night with a straight-sets win over Alexander Zverev.

Here are the photos from the day:

(L-R): Naomi Osaka and Michael Phelps at the US Open

(L-R): Karlie Kloss, Michael Bloomberg, and Jon Batiste at the US Open

Here are the other celebrities spotted at the US Open 2023

(L-R): Barack and Michelle Obama

Throughout the first 10 days of the year's last Grand Slam, many celebrities have flocked to the Arthur Ashe Stadium to watch famous players compete. Former US President Barack Obama and First Lady Michelle Obama, Vogue Magazine editor-in-chief Anna Wintour, fashion designer Vera Wang, actor Alec Baldwin, and others were spotted on Day 1.

Justin Bieber, Hailey Bieber, and Jimmy Butler were seen sitting alongside Frances Tiafoe to watch Coco Gauff's third-round match against Elise Mertens on September 2. Emma Watson, Mariska Hargitay, Retta, Gloria Steinem, J Balvin, were there on Day 8. Former Grand Slam champions have also come down to New York City. This includes 2005, 2009, and 2010 champion Kim Clijsters and 2006 winner Maria Sharapova.

The US Open is now nearing its ultimate stages, with the semifinals set for singles and doubles draws, and the final set for mixed doubles. Novak Djokovic will face Ben Shelton, and Carlos Alcaraz will come up against Daniil Medvedev in the men's singles semifinals. On the women's side, Aryna Sabalenka and Madison Keys, and Karolina Muchova and Coco Gauff will go head-to-head.

The first final at Flushing Meadows will be played on Saturday, September 9, when Jessica Pegula and Austin Krajicek face Anna Danilina and Harri Heliovaara in the mixed doubles title match.