19:08 CET - Amanda Anisimova has kept her hopes of a semi-final spot alive at the WTA Finals in Riyadh, with the American recovering from a set and 3-1 down to defeat compatriot Madison Keys, 4-6, 6-3, 6-2.
She'll now face Iga Swiatek in the final round of group fixtures, with the winner guaranteed of a place in the last four. As for Keys, she's out of the tournament after two losses from her opening two matches.
17:07 CET - Miomir Kecmanovic is the latest to secure victory in Athens, with the Serb winning 7-6, 7-6 in a two-hour battle with Kamil Majchrzak.
16:56 CET - Elena Rybakina is into the last four! The Kazakh has ended her losing streak against Iga Swiatek, beating the world number two 3-6, 6-1, 6-0.
Swiatek's level dropped a huge amount after the opening set, and Rybakina took full advantage.
16:37 CET - Lorenzo Sonego has marched on in Metz, coming from behind to seal a 4-6, 6-4, 6-4 win over Jan Choinski.
16:26 CET - We're going three sets in Riyadh! After losing the opener 6-3, Ryabkina bounced back to win the second 6-1, taking us into a decider.
16:14 CET - It's a Tale of Two Americans in Europe, with Eliot Spizzirri beating Laslo Djere 1-6, 7-6, 6-2 in Athens but Aleksandar Kovacevic losing 6-3, 6-2 to Clement Tabur in Metz.
15:10 CET - Iga Swiatek and Elena Rybakina are about to get underway in the first match of the day in Saudi Arabia.
The stakes are high, with both knowing that a win will guarantee them a spot in the final four of the WTA Finals.
The Pole heads into the clash as the favourite having won each of the last five matches against her opponent. Can Rybakina turn the tide?
14:45 CET - The first results of the day are in, in both Athens and Metz.
In the Greek capital, Damir Dzumhur has claimed a 6-4, 6-2 win over Jacob Fearnley, while Learner Tien has beaten wildcard Ugo Blanchet 6-3, 6-3 on the latter's home turf in Metz.
11:02 CET - Today's headline action comes at the WTA Finals in Riyadh where Iga Swiatek faces Elena Rybakina at 15:00 CET, with both women looking to seal a semi-final spot after wins on Saturday.
Following that match, Amanda Anisimova comes up against American compatriot Madison Keys in a must-win clash for both players.
Elsewhere, there's ATP action at tournaments in Metz and Athens, with Cameron Norrie, Stan Wawrinka and Matteo Berrettini among the standout names taking to the court throughout the day.
Check out the full schedules for Metz and Athens via the links.
10:00 CET - Good morning and welcome to our coverage of today's tennis!