18:38 CET - In the last match of the day in Hangzhou, wild card Zhang Zhizhen has beaten fellow Chinese player Bu Yunchaokete 6-7, 6-4, 7-6 to move into the second round.
Catch up on all the scores from Hangzhou here.
That's all from us today on the Tennis Tracker, but be sure to tune in again tomorrow as the action continues in Seoul, Chengdu and Hangzhou, as well as in the BJK Cup!
16:39 CET - Barbora Krejcikova is through in Seoul after coming from a set down and saving three match points to ultimately outlast Emma Raducanu in three sets, 4-6, 7-6(10), 6-1.
15:51 CET - We're going to a decider in the final match of the day in Seoul after a thrilling second set, in which Barbora Krejcikova fought back from 5-2 down and saved three match points against Emma Raducanu before edging the tiebreak 12-10.
15:14 CET - Great Britain have claimed the last BJK Cup semi-final spot, with Katie Boulter sending her nation through to the final four with a 6-2, 6-1 win over Moyuka Uchijima.
13:58 CET - The reigning champion is out in Hangzhou, with Marin Cilic being beaten 4-6, 6-4, 6-3 by American qualifier Nishesh Basavareddy.
13:24 CET - Gael Monfils has unfortunately been forced to retire from what was a real battle with Alexander Shevchenko in Chengdu, withdrawing with an injury while trailing 6-7, 6-3, 1-0. Shevchenko moves into the next round along with Mackenzie McDonald and Nikoloz Basilashvili, who also prevailed in the final matches of the day.
On the women's side of the game, Sonny Kartal has given Great Britain in their BJK Cup tie with Japan, beating Ena Shibahara 6-3, 7-6, while Katerina Siniakova has claimed a 7-6, 6-2 win over fourth seed Daria Kasatkina in Seoul.
12:28 CET - Ella Seidel is the latest woman through in Seoul after the German came from a set down to outlast sixth seed Beatriz Haddad Maia 6-7(4), 7-6(3), 7-5 in a three-and-a-half-hour epic.
11:23 CET - Iga Swiatek has eased into the quarter-finals in Seoul, with the top seed proving too strong for Sorana Cirstea in a 6-3, 6-2 victory.
10:56 CET - Eighth seed Matteo Berrettini has been dumped out in Hangzhou after the Italian fell to a 6-3, 6-3 defeat against lucky loser Dalibor Svrcina.
Meanwhile, in Chengdu, Taro Daniel and Dino Prizmic are safely through after straight-set wins.
10:49 CET - USA have booked their spot in the last four of the BJK Cup after Jessica Pegula and Taylor Townsend saw off Elena Rybakina and Yulia Putintseva 6-2, 7-6(1) in the decisive doubles rubber to complete a 2-1 victory over Kazakhstan.
They'll now face either Great Britain or Japan in the semi-finals over the weekend.
10:15 CET - Top seed Iga Swiatek is one set to the good in her opening match in Seoul, with the Pole leading Sorana Cirstea 6-3.
Follow the second set with Flashscore here.
Elsewhere, Lorenzo Sonego, Alejandro Tabilo and Tomas Martin Etcheverry have all claimed victories in China.
09:57 CET - Giovanni Mpetshi Perricard is through in Chengdu after recovering from a set down to defeat Filip Misolic 3-6, 6-1, 6-4, while Ekaterina Alexandrova and Suzan Lamens have advanced in Seoul.
09:53 CET - Kazakhstan have levelled their BJK Cup quarter-final against USA, with Elena Rybakina easing past Jessica Pegula in straight sets, 6-4, 6-1.
Follow the decisive doubles rubber here.
07:40 CET - Good morning and welcome to our coverage of today's tennis!
We've got a busy day of action to look forward to in Asia, as top seed Iga Swiatek begins her campaign in Seoul at 08:30 CET, while Emma Raducanu comes up against Barbora Krejcikova in an intriguing clash between two former Grand Slam champions.
Elsewhere, the remaining two quarter-finals at the BJK Cup are also taking place, with USA already 1-0 up on Kazakhstan and Great Britain facing Japan a little later.
Check out the full schedules in Chengdu, Hangzhou and Seoul via the links.
