22:43 CET - The 10th game of the first set proved a pivotal moment as Daniil Medvedev (27) ran away with the second set to win his first group game against Andrey Rublev (26) 6-4, 6-2 for the perfect start to his ATP Tour Finals.
22:06 CET - After a tight tussle in the final game that featured six dueces, Daniil Medvedev has won the opening set against Andrey Rublev 6-4.
21:06 CET - Daniil Medvedev (27) and Andrey Rublev (26) are on court for the final game of the day at the ATP Finals in Turin.
19:29 CET - Some news away from the court where former US Open champion Emma Raducanu (21) has pulled out of a December exhibition match at the Macau Tennis Masters as she continues to recover from wrist and ankle surgery, her management company IMG said on Monday.
17:28 CET - Alexander Zverev (26) has come out on top after all! The German defeated Carlos Alcaraz (20) in Turin after a 6-7, 6-3, 6-4 animated contest.
16:39 CET - Just over half an hour later, and Alexander Zverev (26) has tied it back up, winning the second set 6-3 to take us to a decider against Carlos Alcaraz (20).
16:07 CET - In Turin, Carlos Alcaraz (20) has picked up the first set against Alexander Zverev (26), but he hasn't had it all his own way, needing a tie-break to get over the line and go ahead.
Meanwhile, after last night's win over Holger Rune (20), Novak Djokovic (36) has been confirmed as the end-of-year world number one - something that was celebrated before the start of play in Turin.
5:42 CET - Carlos Alcaraz faces Alexander Zverev, aiming for a positive start to his campaign in the ATP Finals before Daniil Medvedev takes on Andrey Rublev with the same motivation.
Overnight world number one Novak Djokovic defeated Holger Rune 7-6, 6-7, 6-3 after an animated three-hour contest.
