Defending champion Novak Djokovic has been placed in a group with home favourite Jannik Sinner for the ATP Finals in Turin, where he needs to win just one match to end the year again as world No.1.
The draw for the season-ending, eight-man finals was made on Thursday, leaving Djokovic pitted against Stefanos Tsitsipas and Holger Rune as well as Sinner in the Green Group for the round-robin stage.
Second-seeded Carlos Alcaraz headlines the Red Group, which also includes Daniil Medvedev, Andrey Rublev and Alexander Zverev.
The top two from each group in the tournament, which starts on Sunday, will advance to the semi-finals, with the final scheduled for November 19.
Djokovic is bidding to win the event for a seventh time and is hot favourite, having not lost a match since his defeat to Alcaraz in the Wimbledon final in July. He is out to surpass Roger Federer, with whom he shares the record of six titles.
Zverev has won the tournament twice, while Medvedev and Tsitsipas have one victory apiece.