TURIN: Reigning champion Daniil Medvedev moved to the brink of the last four at the ATP Finals on Tuesday by edging out Alexander Zverev 6-3, 6-7 (3-7), 7-6 (8-6) in a dramatic match in Turin. Russian second seed Medvedev missed two match points in a gripping deciding-set tie-break before getting over the line at the third time of asking. Medvedev now leads Zverev 6-5 in their head-to-head, having also beaten him in the round-robin stage last year. Medvedev is not guaranteed a semi-final place yet, though, as defeat by alternate Jannik Sinner in his final group match would leave him level with the young Italian and Zverev, should the German see off Hurkacz. Sinner replaced fellow home hope Matteo Berrettini in the draw and made an immediate impact by thrashing Hurkacz 6-2, 6-2. Wimbledon runner-up Berrettini withdrew due to the abdominal injury which forced him to retire from his first match against Zverev early in the second set. The 20-year-old Sinner made his ATP Finals debut against Hurkacz after Berrettini pulled out of the season-ending event, being staged in Italy for the first time after moving from London. Sinner made the most of his opportunity with a brilliant display against Hurkacz. The world number 11 broke his opponent twice in the opening five games of the match and never looked back, smashing five aces and 17 winners to wrap up victory in under an hour-and-a-half. Novak Djokovic leads the Green Group after beginning his attempt to equal Roger Federer’s record number of ATP Finals triumphs with a straight-sets win over Casper Ruud on Monday. Russian Andrey Rublev also impressed with a 6-4, 6-4 victory over 2019 champion Stefanos Tsitsipas and sits behind Djokovic in the standings by virtue of winning one game fewer than the 20-time Grand Slam champion.