Jannik Sinner and Carlos Alcaraz were placed in different groups for the ATP Finals in Thursday’s draw. The earliest they could meet in the semi-finals.

The Ilie Nastase Group features Sinner, Daniil Medvedev, Taylor Fritz and Alex de Minaur. The John Newcombe Group features Alcaraz, Alexander Zverev, Casper Ruud and Andrey Rublev.

The tournament for the year’s top eight men’s players starts on Sunday and the top two finishers in each group advance to the semi-finals.

Sinner (Australian Open and US Open) and Alcaraz (French Open and Wimbledon) split the year’s four Grand Slam titles between them.

Defending champion Novak Djokovic withdrew on Tuesday citing an injury. The groups are named for the first No. 1s in the ATP rankings: Nastase and Newcombe.