Sinner beats Medvedev at ATP Finals to set up title match against Djokovic or Alcaraz.
Jannik Sinner became the first Italian to reach the final of the ATP Finals by taking a gutsy 6-3 6-7 (4-7) 6-1 victory over Daniil Medvedev.
Sinner, 22, was fired up by the home support in Turin and saw off the Russian in two hours and 29 minutes.
He will face Novak Djokovic or Carlos Alcaraz, who meet in their semi-final on Saturday evening, in Sunday's final.
"It is a privilege to have this kind of pressure. The crowd has given me so much energy," Sinner said.
"It is an incredible feeling because it was a really tough match. I am happy to be in the final."
World number four Sinner's victory was his third straight success against Medvedev, having lost the previous six encounters between the pair.
Sinner held a crucial service game early in the first set to make it 1-1, before backing that up with a break before going on to clinch the set.
The second set was much tighter as Sinner saved the only break point opportunity, only to lose out in the tie-break when he overhit a forehand.
Medvedev handed Sinner the upper hand in the decider, losing his serve with a double fault, and the Italian never looked back.
Sinner produced a superb backhand winner to give himself three match points against the world number three, closing the match out at the first attempt.
"I felt that he was playing more aggressively, especially in the first set. Somehow I made the break and from that point I felt better," added Sinner, who has never been beyond the semi-final of a Grand Slam.
"The second set was really tight, but then he played a very good tie-break. In the third set I just tried to stay a bit more aggressive, mixing up my game a little bit."