Novak Djokovic delivered a masterclass to beat Carlos Alcaraz in the latest instalment of their burgeoning rivalry to reach the ATP Finals showpiece.
The Serb will aim for a record seventh title on Sunday after a 6-3 6-2 win put him through to face Italian Jannik Sinner in Turin.
Sinner became the first Italian to make the season-ending final with a 6-3 6-7 (4-7) 6-1 win over Daniil Medvedev.
In doubles, Britain’s Joe Salisbury and American Rajeev Ram reached the final.
The defending champions beat French-Mexican pair Edouard Roger-Vasselin and Santiago Gonzalez 7-6 (7-5) 3-6 10-7, and will face Argentina’s Horacio Zeballos and Marcel Granollers of Spain for the title on Sunday.
Djokovic at his best against Alcaraz
In a blockbuster encounter between the two players who have dominated the tour this season, Djokovic, 36, was at his ruthless and relentless best against his 20-year-old opponent.
He faced just two break points in the first set, in his opening service game, and delivered stunning back-to-back volleys at the net followed by a smash to hold a seven-minute game for 3-2 – but those were the only real times he faced pressure in the opener.
A loose service game from Alcaraz handed Djokovic a break for 5-3 and the Serb served emphatically out to love.
Djokovic broke early in the second set to tighten his grip on the match but was then in danger of losing the advantage when the Spaniard had two break points in an enthralling sixth game that featured the best tennis of the match.
But the 24-time Grand Slam champion saved them both, including one by delivering a brilliant passing shot at the end of a 23-shot rally, and then went a double break up in the next game.
He then raced to 40-0 when serving for the match before the rare blemish of a double fault, before sealing victory with a smash.
Djokovic has won three of the season’s Grand Slams, beating Alcaraz in the French Open semi-finals, while Alcaraz won the other major by overcoming the Serb in the Wimbledon final.
The pair traded the world number one ranking through the season but Djokovic sealed the year-end top spot earlier this month for a record eighth time, and his performance on Saturday underlined why he remains the player to beat.
But on Sunday he faces a player who has beaten him very recently, Sinner having ended Djokovic’s 19-match winning streak on Wednesday with a three-set victory in the round-robin phase.
If Djokovic plays at anywhere near this level on Sunday, though, the Italian may need to find another gear if he is to repeat that feat.
“This year I wasn’t maybe as sharp in the second and third group matches, particularly, but I think tonight from the very beginning I felt the ball well,” Djokovic was quoted as saying on the ATP Finals website.
“I approached the match with the right attitude, the right mentality, and I knew from the very first point it was going to be greatly intense.”
You can follow live text coverage of Sunday’s final (which will not start before 17:00 GMT) on the BBC Sport website and app.
‘Incredible feeling’ as Sinner delights home crowd
World number four Sinner’s victory was his third straight success against Medvedev, having lost the previous six encounters between the pair.
He has been backed by strong home support all week at the prestigious event and will be hoping for more of the same in the final.
“It is a privilege to have this kind of pressure. The crowd has given me so much energy,” the 22-year-old said.
Sinner held a crucial service game early in the first set to make it 1-1, before backing that up with a break and 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.
“It is an incredible feeling because it was a really tough match. I am happy to be in the final.”