21:07 CET - Carlos Alcaraz is just inevitable, isn't he? A tight second set looked to be going to a tiebreak but at that moment, the world number came alive to break Felix Auger-Aliassime and claim victory.
Alcaraz looked in control throughout, and the win rarely looked in doubt on the way to a 6-2, 6-4 victory.
So.. Jannik Sinner vs Carlos Alcaraz gets one last showdown in 2025 in what has been an epic year of battles between two players in their own league.
20:20 CET - After a settling-in period, Alcaraz took complete control of the first set by producing the type of winners that have become synonymous with the world number one. Alcaraz takes the first set 6-2 after completing a double break.
Auger-Aliassime looks out of ideas as everything he attempts comes back at him with killer speed.
20:45 CET - Play is underway in Turin as Carlos Alcaraz takes on Felix Auger-Aliassime for a place in the final.
19:45 CET - The ATP Finals doubles decider will be contested between Henry Patten & Harri Heliovaara and Joe Salisbury & Neal Skupski.
The latter duo won the second semi-final, in what was an all-British affair, against Julian Cash & Lloyd Glasspool 6-7, 6-3, 10-8 to seal their place in tomorrow's final in Turin.
19:30 CET - In about one hour, Carlos Alcaraz plays Felix Auger-Aliassime for the right to take on Jannik Sinner in the ATP Finals decider tomorrow.
Alcaraz, who is yet to lose in Turin, leads the head-to-head 4-3 and has won all of their previous four meetings, but Auger-Aliassime has been in fine form to end the season and will fancy his chances of an upset today.
You can follow every point of the match here.
16:35 CET - Defending champion Jannik Sinner is back into the final of the ATP Finals - for a third-straight year!
After a really competitive first set, Alex de Minaur simply ran out of gas, with the Italian going on to win 7-5, 6-2 in an hour and 52 minutes. As good as the Australian was, Sinner on an indoor court is virtually unplayable.
He will now be back tomorrow in front of a roaring home crowd, and he awaits the winner of Carlos Alcaraz and Felix Auger-Aliassime, who are in action later.
15:50 CET - Despite a brilliant set of tennis from Alex de Minaur, Jannik Sinner has edged to a lead over the Australian, coming out on top in the big moments to win the opener 7-5.
De Minaur couldn't play any better, yet still came out second best. It is a long way back now, as defending champion Sinner closes in on ATP Finals final.
14:25 CET - We are minutes away from the first singles semi-final of the day, as defending champion and home favourite Jannik Sinner looks to improve his 12-0 head-to-head record against Alex de Minaur. Who will secure their spot in the final?
Follow the clash live with Flashscore!
13:29 CET - It has been a bad start to the day for the fans in Turin, as a brilliant performance from second seeds Henry Patten and Harri Heliovaara has seen them ease to a 6-4, 6-3 win over Italian duo Andrea Vavassori and Simone Bolelli, booking their spots in the doubles final on Sunday!
12:00 CET - Good morning and welcome back to the Tennis Tracker on semi-finals day at the ATP Finals!
The action begins at 14:30 CET, as defending champion Jannik Sinner comes up against Alex de Minaur.
The Italian cruised into the last four with a perfect three wins from three, while the Aussie needed just a single victory to squeeze out of the group.
Unfortunately for De Minaur, he faces a man whom he has played 12 times - and lost on every single occasion. His job will be made doubly hard with the Turin crowd behind Sinner.
Tonight at 20:30 CET, another man who has a perfect record so far at the ATP Finals, Carlos Alcaraz, meets the in-form Felix Auger-Aliassime. The latter won two of his three round robin matches, while losing to Sinner.
Alcaraz leads the head-to-head 4-3 and has won all of their previous four meetings.