Two-time US Open champion Venus Williams is making her 19th appearance in Flushing Meadows, the most among active players and the joint third (with Chris Evert) of the Open Era (after Martina Navratilova's 21 and Amy Frazier's 20). Williams made it to the second week the first 12 times she played in New York, and is bidding to make it a 15th showing at that stage today.
The third round between Maria Sharapova and Sofia Kenin will be a battle of wildcards who were both born in Russia and resident in the USA. It will be the first all-wildcard match at this stage of a major this century, and will guarantee the first wildcard in the second week of the US Open since Alison Riske's fourth-round run in 2013.
Carla Suárez Navarro leads the head-to-head against Ekaterina Makarova 6-2, including 3-1 on hard courts. The Spaniard has also won their last four encounters, including by 6-3, 6-1 in the first round of Eastbourne this year. Makarova's sole victories have come in their first ever meeting, in the Torrent $25,000 ITF event in 2006, and in Doha in 2013 - but the Russian is fresh off overturning an even more emphatic deficit, as she was 0-7 against Caroline Wozniacki before beating the No.5 seed in the second round.
Between Roland Garros 2012 and Roland Garros 2015, Sloane Stephens reached the second week at eight of 13 Slams. She has fallen in the first week at every major she's played since then, and is bidding to change that today.
The head-to-head between No.13 seed Petra Kvitova and No.18 seed Caroline Garcia is all square at 2-2, all on hard courts. Kvitova took the first two, at Wuhan in 2014 and in the Fed Cup semifinals the following year, but Garcia bounced back to take the most recent pair, in Cincinnati in 2015 and the Fed Cup final last year. However, the Frenchwoman is yet to score a Top 50 win at the US Open.
Maria Sharapova, who plays World No.139 Sofia Kenin today, has never lost to an opponent ranked outside the Top 100 at the US Open. Her lowest-ranked conqueror in New York was No.70 Melanie Oudin in the third round in 2009.
Maria Sakkari is looking to become the first Greek woman to make the second week of a Slam since Eleni Daniilidou at the 2004 US Open. Her run here means that she has now made the third round at three of the four majors, with just Roland Garros missing. Sakkari's sole encounter to date with her opponent today, Venus Williams, was a tough 7-5, 4-6, 6-3 loss in the second round of Wimbledon last year - and she is 0-3 against Top 10 opponents overall.
Four of the five previous Slam champions remaining are in the bottom half of the draw: Venus Williams, Maria Sharapova, Petra Kvitova and Garbiñe Muguruza, with Jelena Ostapenko the only Slam champion in the top half. However, seven former junior Slam winners are still in contention, only one of whom - Ashleigh Barty, the 2011 Wimbledon girls' champion - is in the bottom half. (Ostapenko, Daria Kasatkina, Elina Svitolina, Karolina Pliskova, CoCo Vandeweghe, Agnieszka Radwanska and Kaia Kanepi are the junior Slam victors in the top half.)
Both of Aleksandra Krunic's Top 10 wins have come at the US Open - also the site of her Slam debut in 2013 and her memorable run to the fourth round in 2014, beating Petra Kvitova and Madison Keys en route.
Magdalena Rybarikova reached the third round at Flushing Meadows in her first two appearances here in 2008-09. However, she would not reach that stage of any Slam again for the next six years, and has only this year returned to it at the US Open.
Garbiñe Muguruza is currently on a seven-match winning streak, and a win today would equal her second-longest run of WTA main draw wins ever. Previously, she notched up eight in a row between winning Hobart and reaching the fourth round of the Australian Open in 2013, as well as winning Beijing and making the WTA Finals semifinals in 2015. Her longest streak to date was set last month at nine, after following up her Wimbledon title with a Stanford semifinal. (However, counting qualifying matches, her Hobart/Melbourne run can be extended to 11.)
American qualifier Allie Kiick made her Slam debut this year after a two-year hiatus in which she endured four surgeries, mononucleosis and cancer. Find out more about her story from Ava Wallace for the Washington Post.
Jelena Ostapenko is at it again. Steve Tignor explores what makes the free-hitting French Open champion so "exciting and disorienting to watch" for Tennis.com.
18-year-old CiCi Bellis may have lost in the first round to Nao Hibino, but the youngest player in the Top 50 remains one to watch, argues Gerald Marzorati for the New Yorker.
Bellis isn't alone, though: nearly one-third of the women remaining are ages 22 or under. Find out more about them in our Stats Corner.
American Shelby Rogers made history yesterday by winning the longest women's match in US Open history. Find out more with our SAP stat of the day.