22:40 CET - Elsewhere tonight, Novak Djokovic (37) headlines action in Brisbane as he plays his first singles match of the year. Before Djokovic, the Serbian's doubles partner Nick Kyrgios (29) makes his long-awaited return to singles action in front of home support.
Follow the action from Brisbane here.
There are also two fascinating matches in the United Cup as France face Italy and USA take on Croatia with some big names in action.
Follow the United Cup action here.
And finally, there are matches to look forward to in Hong Kong with Denis Shapovalov (25) against Kei Nishikori (35) being the highlight.
Follow the ATP action from Hong Kong here.
22:30 CET - As the end of the day approaches in Europe, a new one is about to get underway in Australia where there is plenty of tennis to look forward to.
First up tonight though is action from Aukland as Sofia Kenin (26) takes on Xiyu Wang (23) before Yuliia Starodubtseva (24) faces Romania's Jaqueline Cristian (26).
Follow all the WTA action from Aukland here.
17:00 CET - Alexander Zverev (27) and Laura Siegemund (36) have secured victory for Germany over China as the Germans win Group E and remain on course to defend their United Cup title.
With the score 1-1 after the singles, it was all the play for this afternoon but Zverev and Siegemund made no mistake by beating Shuai Zhang (35) and Zhizhen Zhang (28) 6-2, 7-6 (7-3).
15:08 CET - In the final singles action before tonight, Cameron Norrie (29) beat NextGen Finals runner-up Learner Tien (19) 6-3, 7-5 in Hong Kong.
13:46 CET - The last women's match of the day in Brisbane has gone the way of Ons Jabeur (30), who has beaten Saisai Zheng (30) 7-6, 6-4 to progress.
12:57 CET - World number two Alexander Zverev (27) has survived a big scare in the United Cup, coming back after losing the first set to beat Zhizhen Zhang (28) of China 2-6, 6-0, 6-2.
11:45 CET - The partnership between Novak Djokovic (37) and Nick Kyrgios (29) has gotten off to a winning start with the duo beating Alexander Erler (27) and Andreas Mies (34) 6-4, 6-7, 10-8 and having a great time doing so. This is going to be a fun week in the doubles.
11:24 CET - A heavyweight clash at the United Cup has been won by world number six Casper Ruud (26) of Denmark, who has beaten Polish star Hubert Hurkacz (27) 7-5, 6-3.
10:40 CET - In the final men's match of the day in Brisbane, third seed Holger Rune (21) has lost 7-5, 6-3 to Jiri Lehecka (23).
10:24 CET - Nick Kyrgios (29) and Novak Djokovic (37) are a set up in their first doubles match together in Brisbane, leading Alexander Erler (27) and Andreas Mies (34).
09:23 CET - The reigning men's champion is through in Brisbane with Grigor Dimitrov (33) beating Yannick Hanfmann (33) 7-6, 6-3 to advance.
At the United Cup meanwhile, women's world number two Iga Swiatek (23) has sent Poland through with a dominant 6-1, 6-0 win over Malene Helgo (25) of Norway.
08:25 CET - Elena Rybakina (25) has beaten Maria Sakkari (29) 6-4, 6-3 to send Kazakhstan through in the United Cup after Stefanos Tsitsipas (26) was beaten 6-4, 7-6 by Alexander Shevchenko (24) earlier in the night.
In Brisbane meanwhile, Jordan Thompson (30) has won 3-6, 6-3, 6-4 against Matteo Berrettini (28), and Naomi Osaka (27) has beaten Lina Glushko (24) 6-4, 6-4 in Auckland.
05:15 CET - Tomas Etcheverry (25) came from a set down to defeat Billy Harris (29) 3-6, 6-3, 6-2 to tie the match-up at one apiece. Etcheverry and Podorska will return to the court for the all-important decider against Boulter and Charles Broom (26) to determine the winner between the two.
02:30 CET - Katie Boulter (28) of Great Britain defeated Nadia Podorska (27) from Argentina 6-2, 6-3 in the United Cup to give her country a 1-0 lead. The world number 24 won 81% of her first serve points to defeat the 100th-ranked player in 87 minutes.
22:30 CET - Welcome back to the Tennis Tracker this evening, as tournaments in Brisbane, Auckland and Hong Kong really begin to get moving.
Throughout the next 24 hours, the likes of Holger Rune (21), Grigor Dimitrov (33), Matteo Berrettini (28), Naomi Osaka (27) and Ons Jabeur (30) are all set to be in action, while the duo of Nick Kyrgios (29) and Novak Djokovic (37) begin their doubles partnership in Brisbane.
Elena Rybakina (25), Stefanos Tsitsipas (26), Alexander Zverev (27), as well as Iga Swiatek (23), also commence their 2025 seasons as part of Monday'sa ction.