Wednesday, August 20th
08:38 CET - There was plenty of action overnight, with the standout result coming in Winston-Salem, where top seed Stefanos Tsitsipas fell to a disappointing 6-3, 6-2 defeat against Yunchaokete Bu.
Elsewhere, Linda Noskova, Ajla Tomljanovic and Alycia Parks were among the women to progress in Monterrey.
Check out all the results in Cleveland, Monterrey and Winston-Salem via the links.
00:05 CET - In the final match of the day at the US Open mixed doubles event, late replacements Danielle Collins and Christian Harrison have continued on their way, beating Ben Shelton and Taylor Townsend 4-1, 5-4(2) to move into the semi-finals.
Tuesday, August 19th
23:49 CET - Top seeds Jessica Pegula and Jack Draper look really, really good. The duo have been in terrific touch today, and have now seen off Mirra Andreeva and Daniil Medvedev 4-1, 4-1 to book their spots in tomorrow's semi-final.
23:10 CET - After being announced as late replacements this morning, American duo Danielle Collins and Christian Harrison have eased to a straightforward 4-0, 5-3 win over Belinda Bencic and Alexander Zverev.
22:58 CET - Daniil Medvedev and Mirra Andreeva have booked their spots in the US Open mixed doubles quarter-finals after a relatively comfortable 4-2, 5-3 win over 24-time Grand Slam champion Novak Djokovic and Serbian partner Olga Danilovic.
22:25 CET - Around the tennis world, Giovanni Mpetshi Perricard and Eva Lys have both claimed wins in Winston-Salem and Cleveland, respectively.
21:54 CET - The much-talked-about partnership of Emma Raducanu and Carlos Alcaraz have been dumped out in the last 16, losing to an impressive performance by top seeds Jessica Pegula and Jack Draper 4-2, 4-2. It was an entertaining match with some incredible shotmaking from Alcaraz, and the fans were well into it.
Meanwhile, American duo Taylor Townsend and Ben Shelton clinched a 4-2, 5-4(2) victory over Amanda Anisimova and Holger Rune, cementing themselves as one of the teams to beat at the tournament.
20:36 CET - Iga Swiatek/Casper Ruud and Sara Errani/Andrea Vavassori are into the US Open mixed doubles semi-finals after wins over Caty McNally/Lorenzo Musetti and Karolina Muchova/Andrey Rublev, respectively.
The pairing of Errani and Vavassori is on a mission to defend their crown and beat all the singles stars, and they certainly have been pumped up. Meanwhile, Swiatek has now won three matches in around 19 hours. Not bad.
20:29 CET - Over in Cleveland, Anastasia Zakharova is the first winner of the day after a 6-4, 6-3 win over home favourite and eighth seed Hailey Baptiste.
19:27 CET - One of the more dominant wins so far comes from the pairing of Iga Swiatek and Casper Ruud, despite Swiatek playing less than 24 hours after winning the title in Cincinnati.
The duo made light work of Madison Keys and Frances Tiafoe to win 4-1, 4-2 in just 40 minutes.
Next up? quarter-finals time...
19:18 CET - Andrey Rublev and Karolina Muchova are the next duo through after playing their part in the game of the tournament so far.
It was a statement performance against home favourites Venus Williams and Reilly Opelka as they won 4-2, 5-4 (7-4) in a thrilling encounter packed full of excitement.
18:22 CET - These matches will come thick and fast because we have our second winner!
An impressive display by Caty McNally and Lorenzo Musetti has seen them cruise past the exciting duo of Naomi Osaka and Gael Monfils 5-3, 4-2 to become the second quarter-finalists.
McNally has a good doubles record, and Musetti is one of the best players in the world, so it is no surprise they have worked well together.
17:57 CET - A statement win from the holders as their doubles experience showed in a dominant 4-2, 4-2 victory against ATP and WTA stars Taylor Fritz and Elena Rybakina in the US Open mixed doubles gets started.
17:10 CET - The wait is over, the highly anticipated US Open Mixed doubles is here and underway as Elena Rybakina and Taylor Fritz take on the defending champions Sara Errani and Andrea Vavassori.
Following on from the news we reported earlier, Danielle Collins and Christian Harrison have now replaced Sinner and Siniakova in the draw.
15:40 CET - As expected, following his retirement in yesterday's Cincinnati final due to illness, Jannik Sinner has withdrawn from the US Open mixed doubles tournament, which he was set to play in alongside Katerina Siniakova.
It is not yet known who will replace them, or whether Siniakova will simply get a new partner.
15:00 CET - Welcome back to the Tennis Tracker this afternoon, and today begins the brand new, reimaged US Open mixed doubles event!
The shortened, revamped format has lured in the world's best singles players, and as a result, some of the match-ups are so exciting.
Play begins at 17:00 CET, with Elena Rybakina/Taylor Fritz facing defending champions Sara Errani/Andrea Vavassori, while Naomi Osaka/Gael Monfils come up against Caty McNally/Lorenzo Musetti.
There are several great clashes throughout the day, including top seeds Jessica Pegula/Jack Draper clashing with Emma Raducanu/Carlos Alcaraz, and Olga Danilovic/Novak Djokovic vs Mirra Andreeva/Daniil Medvedev. 45-year-old Venus Williams and Reilly Opelka are also set to team up.
Away from the US Open, there is plenty of singles going on.
Hailey Baptiste, Evs Lys, and young starlet Iva Jovic are all in action in Cleveland, with play also starting at 17:00 CET.
Meanwhile, a little later tonight, Rebecca Sramkova and Linda Noskova take to the court in Monterrey, while Stefanos Tsitsipas begins his Winston-Salem campaign.