TURIN, Italy -- Top-ranked Jannik Sinner became the first player to advance to the semifinals at the ATP Finals on Thursday.
Sinner was assured of a spot in the last four after US Open finalist Taylor Fritz beat Alex de Minaur 5-7, 6-4, 6-3 in their group.
Sinner won his opening two matches and plays Daniil Medvedev later Thursday. Last year, Sinner lost the final to Novak Djokovic, who is not playing this year due to injury.
Fritz also has two wins, while Medvedev is still in contention and could get to two wins by beating Sinner. De Minaur was mathematically eliminated without any wins in his finals debut.
The top two finishers in each group advance to the semifinals. The Sinner-Medvedev match will determine whether the other qualifier is Fritz or Medvedev.
"If I don't get through, it's going to be tough because I did play two very good matches and lost to the best player in the world," Fritz said of his loss to Sinner. "But if that happens, I'm happy with my week and I'll leave with my head held high. But I'll definitely be checking in on the score tonight."
Alexander Zverev leads the other group ahead of Casper Ruud, Carlos Alcaraz and Andrey Rublev.
Fritz improved to 4-5 in his career against De Minaur and could pull level next week in a quarterfinal matchup between the United States and Australia at the Davis Cup Finals.
"I feel like he typically plays better in the team environment. I also feel like I play better in the team environment," Fritz said. "It's still going to be a nightmare to play him next week too."