TURIN, Italy -- He's got a stranglehold on the No. 1 ranking. He's unbeaten this week and hasn't dropped a set. And his home Italian fans can't get enough of him.
Things couldn't get much better for Jannik Sinner at the ATP Finals so far -- despite an ongoing doping case that likely won't be decided until early next year.
Sinner and US Open finalist Taylor Fritz advanced to the semifinals Thursday at the season-ending tournament for the year's top eight players.
Sinner won the round-robin group after a 6-3, 6-4 victory over 2020 champion Daniil Medvedev; and Fritz advanced in second after rallying past Alex de Minaur 5-7, 6-4, 6-3.
Sinner was already assured of a spot in the last four even before his match against Medvedev but still extended his winning streak to nine matches. Sinner beat Fritz in the US Open final in September for his second Grand Slam title.
"I hope this match gives me confidence for the semifinals, where I'm hoping to raise the level," Sinner said. "But honestly, I'm happy with the level I'm playing at right now."
Sinner is playing at home for the first time since it was announced before his US Open title that he tested positive in two separate drug tests this year.
A decision to clear Sinner of wrongdoing was appealed by the World Anti-Doping Agency in September, and a final ruling in the case is expected in 2025.
"I have been in this position three times already. Three times we had the hearing. Three times (went) my way," Sinner said. "Of course, it's not a position where I like to be in. But I'm going to work together with everyone, like I did before, then we see what comes out. I'm very positive of how it's going to be."
Medvedev, who won one of three matches, and De Minaur, who didn't win any, were eliminated.
Last year, Sinner lost the final to Novak Djokovic, who pulled out injured this year.
Alexander Zverev leads the other group ahead of Casper Ruud, Carlos Alcaraz and Andrey Rublev.
Sinner took the edge in his career meetings with Medvedev at 8-7 -- after Medvedev swept their first six matches.
"He's in full confidence right now," Medvedev said. "I watched his practice before the match - barely misses a shot and he hits strong. Many times a lot of players that don't miss a lot, at least they don't hit strong. He can hit strong - very strong, probably one of maybe top three, four, five hitters on tour, and doesn't miss."
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."