Rafael Nadal was on Thursday drawn in the same group as defending champion Stefanos Tsitsipas and US Open winner Dominic Thiem for the ATP Finals in London.
World number one Novak Djokovic will face Daniil Medvedev, Alexander Zverev and Diego Schwartzman in the group stages of the final addition of the tournament in London before it moves to Turin next year.
The 50th anniversary of the first staging of the event has been marked with the naming of two round-robin groups, Tokyo 1970 and London 2020.
Nadal appears to have the harder route to the semi-finals with Andrey Rublev completing the Tokyo 1970 group alongside Tsitsipas and the winners of the last two Grand Slams.
The tournament, which starts on Sunday, will be held behind closed doors at the O2 arena.
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