Carlos Alcaraz has avoided a nightmare group of death at the ATP Finals.

The Spaniard dropped to No. 3 in the world this week, meaning he was at risk of being draw in the same pool as Jannik Sinner for the round-robin matches.

But Alcaraz has been drawn in the John Newcombe group with Alexander Zverev while Jannik Sinner heads up the Ilie Nastase group.

Joining world No. 2 Zverev and Alcaraz in the Newcombe group will be Casper Ruud and Andrey Rublev.

Meanwhile, Sinner will face Daniil Medvedev, Taylor Fritz and debutant Alex de Minaur in the Nastase group.

It means this year's two Grand Slam champions can only meet in either the semi-finals or final.

Players face off against the other members of their group in the round-robin stage. The top two players with the most wins in each group get to advance to the last four.

Defending champion and overall seven-time winner of the tournament, Novak Djokovic, pulled out on Tuesday despite qualifying sixth in the race. "I was really looking forward to being there, but due to an ongoing injury I won't be playing next week," he said.

His withdrawal meant Ruud, De Minaur and Rublev qualified, completing the line-up. There were fears that organisers would be forced to postpone Thursday's draw ceremony before Djokovic pulled out as the last few spots would not yet have been confirmed.

Sinner will be hoping to lift his first official tour-level trophy in his home country after finishing as the runner-up last year. The world No. 1 is expected to De Minaur in his opening match while Medvedev will face Fritz.

Meanwhile, Zverev will likely begin his campaign against Rublev and Alcaraz's first rival will be Ruud.

Sinner has already been practising inside the Inalpi Arena with Fritz, before learning the American would be one of his rivals in the Nastase group.

The world No. 1 had a memorable outing at last year's ATP Finals. Sinner won all three of his round-robin matches, beating Djokovic in the process.

It brought the Serb's four-month, 19-match winning streak to an end. But Djokovic got revenge in the final, defeating Sinner when they met again with the title on the line.

Ahead of this year's edition, the Italian said: "In Turin last year I played very well losing in the final, but every year the situation is different. The first step will be to start in the best way. The future cannot be predicted, but it will be a very important tournament for me."

In the doubles draw, No. 1 seeds Marcelo Arevalo and Mate Pavic head up the Bob Bryan group. They're joined by home hopes Simone Bolelli and Andrea Vavassori, Rohan Bopanna and Matt Ebden, and Kevin Krawietz and Tim Puetz.

Meanwhile, the Mike Bryan group consists of No. 2 seeds Marcel Granollers and Horacio Zeballos, Wesley Koolhof and Nikola Mektic, Max Purcell and Jordan Thompson, and Harri Heliovaara and Henry Patten.