No.2 seed Ashleigh Barty is 3-1 against No.30 seed Maria Sakkari, including 2-0 this season and once in the US Open series - a 5-7, 6-2, 6-0 victory for the Australian in the Cincinnati quarterfinals two weeks ago to go with her 7-5, 6-1 win in the third round of the Australian Open. Sakkari's sole win came last year, 6-4, 6-2, in the second round of Indian Wells. The Greek player is 0-6 in Grand Slam third rounds - the most times any active player has reached this stage without getting to the fourth round (tied with María José Martínez Sánchez, now solely a doubles player). A second-week debut for her would also be the first time a Greek woman has reached the fourth round of a major since Eleni Daniilidou at the 2004 US Open.
No.5 seed Elina Svitolina and No.32 seed Dayana Yastremska will clash for the first time in an intergenerational all-Ukrainian derby, the second all-Ukrainian Grand Slam third round in history following Svitolina's defeat of Marta Kostyuk at the Australian Open last year. Svitolina is 4-0 against compatriots at Tour level, and indeed her last loss to a fellow Ukrainian was in an ITF W50 event in Nantes in 2012, where Olga Savchuk defeated her 6-4, 2-6 7-5 in the second round. By contrast, this will be the first time Yastremska - who will be bidding for her first Top 10 win - has faced a countrywoman in a WTA-level main draw.
No.10 seed Madison Keys and No.20 seed Sofia Kenin have played twice before, both this year, with Kenin winning 6-7(2), 6-3, 6-4 in the second round of Rome and Keys gaining revenge with a 7-5, 6-4 triumph two weeks ago in the Cincinnati semifinals. Keys is seeking to make the second week of the US Open for the fifth year running.
Karolina Muchova, who faces No.8 seed Serena Williams for the first time, has four Top 20 wins under her belt - all at Slams. The Czech first turned heads at last year's US Open when, as a qualifier ranked World No.202, she upset Garbiñe Muguruza; since then, she has also defeated Anett Kontaveit at both Roland Garros and Wimbledon as well as scoring a career-best win over Karolina Pliskova to make the Wimbledon quarterfinals.
No.18 seed Wang Qiang is one of only two players in the Top 20 yet to reach the second week of a major (along with Bianca Andreescu), and is seeking to rectify that against Fiona Ferro, who is making her debut at the third-round stage. Wang, who is 0-3 in Grand Slam third rounds so far, leads the head-to-head against the Frenchwoman 3-1, including 2-1 this year and once last week, 6-1, 6-4 in the second round of The Bronx. The Chinese No.1 also beat Ferro 6-4, 6-3 in the first round of the Australian Open in January, but lost 6-7(4), 6-3, 6-3 in the second round of Strasbourg on clay.
No.12 seed Anastasija Sevastova and No.22 seed Petra Martic will meet off clay for the first time today. Previously, the pair had split two meetings, with Martic winning 6-1, 6-1 in the third round of Roland Garros 2017 and Sevastova gaining revenge 7-6(4), 6-2 to win the 2018 Bucharest final. The US Open is the only major at which Martic is yet to reach the second week; by contrast, Sevastova has reached two quarterfinals and a semifinal here in the past three years.
No.16 seed Johanna Konta and No.33 seed Zhang Shuai meet at the US Open for the second time - with the first coming in the final qualifying round in 2012. Konta took that 6-4, 3-6, 7-5, and it remains the only three-setter the pair have played: Zhang took their next meeting in Guangzhou the following year, but in 2016 Konta racked up three wins at the Australian Open, Wuhan and Beijing without losing more than four games in any set to take a 4-1 head-to-head lead. The Briton is 7-0 in Grand Slam third rounds, and will bid to make her third appearance in the US Open fourth round following 2015 and 2016.
Ons Jabeur is the first Tunisian woman to reach the third round of the US Open. It is the 25-year-old's second appearance at this stage of a major following Roland Garros 2017. A win against No.3 seed Karolina Pliskova would make Jabeur the first ever Arab woman to reach the second week of a a major.
Two Chinese women, Zhang Shuai and Wang Qiang, have made the last 32 of the US Open for the first time since 2013, when Li Na reached the semifinals and Zheng Jie the third round.
Seven players have made at least the third round of every major this season: Ashleigh Barty, Karolina Pliskova, Elina Svitolina, Serena Williams, Belinda Bencic, Elise Mertens and Petra Martic. Barty is the only one with a shot at making the second week at all four.
Following the second-round defeats of Kristina Mladenovic and Peng Shuai, a brand new US Open quarterfinalist is guaranteed to emerge from the bottom eighth. Ashleigh Barty is the only player remaining in it who has reached the fourth round of a major before, having debuted at that stage here last year.
ORDER OF PLAY
For full order of play, visit usopen.org.
Venus Williams may have fallen in the second round to Elina Svitolina - but the way in which she is still finding ways to compete despite her body betraying her is reminiscent of French painter Henri Matisse, writes Soraya Nadia McDonald for The Undefeated.
In comparison with many other up-and-comers, Sofia Kenin's rise into the Top 20 has been relatively under-the-radar - but the American is here to stay, writes Nina Pantic for tennis.com.
Over the years, the hype machine had turned on former junior prodigy Taylor Townsend - but after pulling off the upset of the tournament over Simona Halep, the American has been turning the doubts into motivation, finds WTA Insider Courtney Nguyen.