Preview ATP Finals Day Six: Zverev and Auger-Aliassime battle in winner-takes-all; Sinner meets eliminated Shelton.

It is the final day of the Round Robin phase of the ATP Finals, where the last semi-finalist will be determined. Defending champion Jannik Sinner will take the court with his spot already secured as the leader of the Bjorn Borg Group, and he will face an already eliminated Shelton, who is playing for the chance to finish the year as American No. 1.

In the decisive match of the day, Felix Auger-Aliassime and Alexander Zverev will take the court, both aiming to join Sinner in the semi-finals. The winner of the match will advance as the second-place player in the group and will face Carlos Alcaraz, while the loser will conclude their participation in Turin.

Jannik Sinner will take the court having already lost the dream of finishing the year as No. 1—following Alcaraz's victory over Musetti—but still with the ambition to defend his 2024 title and the points as undefeated champion. Looking ahead to 2026, the Italian must not lose sight of Alcaraz, and another victory in the Round Robin will allow him, at least, not to let the Spaniard escape further in the rankings.

The 4-time major champion has proven to be the most effective player on indoors during the last seasons: he holds 28 consecutive wins on the surface, during which he has conceded just 3 of the 59 sets he has played. Furthermore, he is on a streak of 7 consecutive victories at the ATP Finals, all in straight sets.

Ben Shelton arrives mathematically eliminated, but still with a lot at stake. The American seemed like a name who could make noise in Turin, but he ultimately came up short, squandering several set points against Zverev, and letting a tie-break slip away against Auger-Aliassime that could have given him the victory.

The American has fallen 4 spots in the live ranking these past few days and is positioned as World No. 9, being the only player at these ATP Finals who has not earned a win. Everything is so tight that taking a victory—though of little value for his chances of qualifying—could propel him in the ranking as high as the Top 5, an important difference ahead of the Australian Open, where the top 8 seeded positions will be highly coveted. Advancing in the ranking would also drag the eliminated Fritz down a bit more, which would give Shelton the chance to finish the year as American No. 1.

The H2H is currently favorable to Sinner at 7-1, and Shelton only managed to win their first encounter at the 2023 Shanghai Masters. Since then, Sinner has faced no issues against the American, taking the following 17 sets they have played against each other.

Zverev will have to recover from the loss in the second match against Jannik Sinner, after a strong performance in which he failed to convert any of his 7 break points in his favor. The German is in his 8th participation at the ATP Finals, a tournament he won in 2018 and 2021, and in which he will be seeking his 5th time reaching at least the semi-finals. Despite falling a step behind Sinner and Alcaraz in the last year, 'Sascha' managed to secure his year-end ranking as World No. 3 regardless of what happens in the coming days in Turin. “I hope to see him again this week,” Zverev assured after the loss to Sinner.

Unlike what happened in the Jimmy Connors Group—where everyone arrived with chances to advance on the final day—this time only Felix and Zverev are playing for their destiny to advance. The Canadian salvaged a match that seemed almost lost against Ben Shelton and recovered his hope of advancing.

Indoor conditions are always favorable to the Canadian, who, with his serve as his main weapon, managed to be one of the most consistent players at the end of the season, earning a last-minute spot in the ATP Finals. Auger-Aliassime will be seeking to reach the semi-finals of the ATP Finals for the first time, and a victory would also put him in the Top 5 for the first time in his career—something that seemed very distant a couple of months ago.

The German dominates the H2H 6-3, including their only two encounters on indoor hardcourts (Cologne 2020, Vienna 2021). However, Auger-Aliassime was the winner in their most recent meeting at the US Open third round, and he arrives on an inspired end-of-year run. He has already become the tennis player with the most indoor hard-court matches this decade (84), and in the victory against Shelton, he showed resilience when he was two points away from defeat.