18:39 CET - Top seed and defending champion Karen Khachanov has been dumped out in Almaty, with the Russian falling 4-6, 7-6(5), 6-3 to Jan-Lennard Struff.
Meanwhile in Brussels, Felix Auger-Aliassime has come through a three-set thriller, edging Damir Dzumhur 7-6(3), 4-6, 7-6(5) in just under three hours.
18:03 CET - Tomas Martin Etcheverry has advanced in Stockholm, with the Argentine battling past Miomir Kecmanovic in three sets, 6-4, 4-6, 6-3.
16:42 CET - Third seed Elena Rybakina is the final woman through to the quarter-finals in Ningbo after a hard-fought 6-4, 6-7(6), 6-3 victory over Dayana Yastremska.
15:15 CET - Lorenzo Sonego has won the first match of the day in Stockholm, beating Aleksandar Kovacevic 7-6, 6-1 to move into the quarter-finals.
14:39 CET - Giovanni Mpetshi Perricard is through to the quarter-finals in Brussels after his opponent Nikoloz Basilashvili was forced to retire with injury, having lost the opening set 7-5.
12:41 CET - Almaty second seed Daniil Medvedev was pushed to the brink by Australian Adam Walton, but the Russian is through with a 7-5, 7-6(0) victory.
Meanwhile, over in Ningbo, fourth seed Ekaterina Alexandrova is into the quarter-finals thanks to a 6-3, 6-3 win over home favourite Yue Yuan.
10:54 CET - Second seed Jasmine Paolini has sailed into the last eight in Ningbo after a convincing 6-2, 7-5 triumph over Veronika Kudermetova.
Elsewhere, Viktorija Golubic is through in Osaka after coming from behind to beat fifth seed Marie Bouzkova 1-6, 6-2, 7-6(5), while Shintaro Mochizuki has advanced to the quarter-finals in Almaty.
09:47 CET - McCartney Kessler is through to the quarter-finals in Ningbo after an impressive 7-6(5), 6-1 victory over eighth seed Liudmila Samsonova.
09:42 CET - Alex Michelsen has advanced in Almaty thanks to a routine 6-3, 6-2 win against Aleksandar Vukic, while Tereza Valentova is through in Osaka after shocking third seed Elise Mertens, 6-4, 6-1.
07:50 CET - Good morning and welcome to our coverage of today's tennis!
We've got a packed schedule to look forward to, with tournaments continuing in Ningbo, Osaka, Stockholm, Brussels and Almaty, while there are a couple of blockbuster semi-finals at the Six Kings Slam in Saudi Arabia.
There have already been a couple of early results in Japan, with fourth seed Leylah Fernandez cruising past Dalma Galfi 6-1, 6-4 and Rebecca Sramkova surviving a second-set wobble to defeat Ann Li 6-2, 3-6, 6-3.
