Jannik Sinner is the two-time defending champion and a four-time qualifier for the Nitto ATP Finals.

It has been a historic season for Sinner, who won the first five ATP Masters 1000 tournaments of the season, becoming the first player to achieve the feat. The Italian won 30 consecutive matches from the start of Indian Wells through the first round at Roland Garros.

Sinner first competed in the season finale as an alternate in 2021 and then returned as a first-time qualifier in 2023. He has won 15 of his 17 matches at the event, reaching the final in 2023 and claiming glory in 2024 and 2025.

Sinner will try to become just the fourth player to win at least three consecutive Nitto ATP Finals titles. Only Ilie Nastase, Ivan Lendl and Novak Djokovic have done so.