18:53 CET - Australia's Kimberly Birrell is into the Chennai final after a three-hour and 19-minute slugfest against Joanna Garland, winning 6-7(2), 6-3, 7-5.
18:39 CET - An imperious performance from the in-form Elena Rybakina has seen her claim a demolishing 6-3, 6-1 win over WTA Finals debutant Amanda Anisimova in just under an hour. The Kazakh squeezed into the competition after a superb few weeks, and she is now making it count.
18:15 CET - Alexander Zverev certainly wasn't fully fit, but Jannik Sinner was utterly sensational as he crushed the defending champion 6-0, 6-1 to ease into the Paris final. Can anyone lay a glove on the Italian on indoor hard courts?
A win in the final tomorrow for Sinner would see him return to world number one.
17:16 CET - Iga Swiatek has begun her WTA Finals campaign in typically ruthless and authoritative fashion, soaring to a crushing 6-1, 6-2 victory over Madison Keys in just over an hour. An early statement made from the Pole.
16:20 CET - Felix Auger-Aliassime's recent resurgence shows absolutely no sign of slowing down, with the Canadian claiming a brilliant 7-6(3), 6-4 victory over Alexander Bublik to seal his spot in the Paris Masters final!
The Canadian has been in superb form over the last few months, resulting in him reaching a second Masters final. With this victory, he has also leapfrogged Lorenzo Musetti into eighth in the ATP Race to Turin, putting himself in pole position to take the final spot.
16:10 CET - Right then, the WTA Finals is about to get underway, with Iga Swiatek taking on Madison Keys in the opening round-robin encounter. It is going to be a great week of tennis!
Follow that clash live with Flashscore!
15:05 CET - In the first semi-final in Chennai, Janice Tjen has edged Lanlana Tararudee 7-6, 7-6 to reach tomorrow's final.
In the second semi, Kimberly Birrell is taking on Joanna Garland.
13:50 CET - It's almost time to move our attention to Paris and Riyadh. The Masters semi-finals will get underway at 14:30 CET, with Felix Auger-Aliassime taking on Alexander Bublik. Then, world number two Jannik Sinner faces number three Alexander Zverev in a blockbuster clash.
Follow the Paris Masters live here.
At 16:00 CET, the WTA Finals will get going with world number two Iga Swiatek taking on Madison Keys. The other Group B participants, Amanda Anisimova and Elena Rybakina, follow.
Follow the WTA Finals live here.
11:30 CET - 17-year-old Lilli Tagger of Austria has stunned second seed Viktorija Golubic 6-1, 4-6, 7-5 to reach the Jiujiang final in China.
The teenager will take on Russia's Anna Blinkova tomorrow in what will be her first Tour final, in what is, would you believe it, her first-ever WTA main-draw appearance! Exciting times for Tagger.
10:24 CET - Rising Canadian star Victoria Mboko has come back to beat her compatriot, and second seed, Leylah Fernandez 2-6, 6-3, 6-2 to qualify for the final of the Hong Kong Open.
Mboko will take on Spain's Cristina Bucsa in the decider tomorrow. The 19-year-old will be seeking her second WTA Tour title.
08:57 CET - Russia's Anna Blinkova has beaten Czech Dominika Salkova 6-4, 6-4 to reach the final in Jiujiang, China.
Blinkova will take on the winner of second seed Viktorija Golubic and 17-year-old Lilli Tagger in tomorrow's final.
08:05 CET - We have our first finalist of the weekend confirmed, and it's Cristina Bucsa. She has defeated fifth seed Maya Joint in the first semi-final in Hong Kong, 6-3, 6-1, in less than an hour.
Leylah Fernandez and Victoria Mboko face off next for the right to play the Spaniard in the decider tomorrow.
06:30 CET - Hello and welcome to our coverage of the ATP and WTA action for this Saturday. It's semi-final day in this week's tournaments, and so we have some great tennis in store!
The Jiujang, Hong Kong and Chennai semis are starting nice and early, with the pick of those women's matches being an all-Canadian clash in Hong Kong between Leylah Fernandez and Victoria Mboko.
Later on, the action heats up in Paris with the last four men hitting the courts.
First up in the French capital, Felix Auger-Aliassime takes on Alexander Bublik at 14:30 CET, before world number two Jannik Sinner faces number three Alexander Zverev in a heavyweight clash.
However, the main events today are the first matches of the WTA Finals in Riyadh!
We have the first two Group B clashes to enjoy later, with world number two Iga Swiatek taking on Madison Keys at 16:00 CET before Amanda Anisimova faces Elena Rybakina.
Stay tuned for all those results and more!