23:39 CET - That's a wrap on today's action, but we'll be back early tomorrow to cover a day featuring Stefanos Tsitsipas vs Lorenzo Musetti, Victoria Mboko vs Bianca Andreescu and much more.
See you then!
22:46 CET - In the last match of the opening day in Basel, seventh seed Jakub Mensik has beaten Swiss hope Henry Bernet, but the 18-year-old put up quite the fight, losing 7-6, 6-7, 6-3 after two and a half hours.
22:32 CET - The fifth seed and last year's runner-up has been knocked out in the Austrian capital, with Karen Khachanov losing 6-3, 5-7, 6-4 to Dutch number one Tallon Griekspoor after just over two hours.
19:04 CET - Third seed Alex de Minaur has sailed into the next round in Vienna after an emphatic 6-4, 6-1 win against wildcard and home favourite Jurij Rodionov.
17:57 CET - In Vienna, qualifier Matteo Arnaldi is into the last 16 thanks to a 7-5, 6-4 victory over American qualifier Aleksandar Kovacevic.
Meanwhile, play is all done for the day in Guangzhou where Chinese wildcard Yafan Wang has sent her fans home happy after beating Kamilla Rakhimova 6-2, 6-4.
17:50 CET - Over to Basel, where Lorenzo Sonego has been knocked out by Alejandro Davidovich Fokina to make it into the next round with a 7-6(2), 6-4 win.
Another Spaniard is also through in Switzerland with Juame Munar getting past home qualifier Remy Bertola in straight sets 6-2, 6-4.
17:22 CET - Ahead of next month's Davis Cup Finals, Jannik Sinner has decided not to take part for reigning champions Italy. World number one Carlos Alcaraz, however, will represent Spain in the Final 8.
"Jannik Sinner has not given his availability for 2025," Italian captain Filippo Volandri said.
"The Davis Cup is, and will remain, always his home and I am sure that Jannik will soon be part of the team again. In the meantime, I can count on a group ready to fight and give everything for the blue jersey."
17:10 CET - Eighth seed Alexander Bublik has eased through in Vienna after a routine 6-4, 6-4 triumph over Alejandro Tabilo in just 69 minutes.
16:28 CET - Elisabetta Cocciaretto tried her best to lose against Diane Parry in Guangzhou, but the Italian is into the last 16 with a 6-4, 6-7(7), 6-2 victory.
15:54 CET - Brandon Nakashima is safely through to the next round in Vienna after a convincing 6-2, 7-5 win over Italy's Luciano Darderi.
15:30 CET - The first match of the year at the Swiss Indoors in Basel has been won by Jenson Brooksby, with the American beating Alexandre Muller 6-4, 6-3.
13:08 CET - Over in Guangzhou, Veronika Erjavec is through after a battling 6-4, 6-7(7), 6-2 victory over Tatjana Maria, while home favourite Xiyu Wang has seen off Francesca Jones 6-4, 6-4.
11:33 CET - Eighth seed Karolina Muchova has progressed to the next round in Tokyo after her opponent Marketa Vondrousova was forced to retire with injury, while trailing 6-2, 1-0.
09:02 CET - Talented Aussie teenager Maya Joint is through in Tokyo after a 1-6, 7-6(5), 6-2 comeback triumph over Viktorija Golubic, while Anna Kalinskaya has beaten Suzan Lamens 6-3, 6-1.
07:53 CET - We've had a couple of early results in Tokyo, with McCartney Kessler recovering from a set down to beat Cristina Bucsa 3-6, 7-5, 6-3 and Eva Lys powering her way past Katie Boulter in straight sets, 6-2, 6-1.
Varvara Gracheva has also advanced in Japan after a hard-fought 4-6, 6-3, 6-4 win over Xinyu Wang.
Looking ahead to the rest of the day, the standout match comes at 10:00 CET, when Karolina Muchova takes on former Wimbledon champion and compatriot Marketa Vondrousova in Tokyo.
Elsewhere, Alex de Minaur and Karen Khachanov open their campaigns in Vienna, while there's also plenty of intriguing first-round action in Basel and Guangzhou.
07:30 CET - Good morning and welcome to our coverage of today's tennis!