Sensational Sinner twice beats Djokovic to send Italy into Davis Cup final
Italy, who won the trophy for the first and only time in 1976, will face 28-time winners Australia on Sunday.
Sinner, who has now triumphed three times in four clashes across 11 days against Djokovic, crucially kept Italy in the tie by beating the 24-time Grand Slam winner 6-2, 2-6, 7-5 in the second singles rubber.
Sinner and Lorenzo Sonego then defeated Djokovic and Miomir Kecmanovic 6-3, 6-4 in the decisive doubles to clinch victory, after Kecmanovic had dispatched Lorenzo Musetti 6-7 (7/9), 6-2, 6-1 in the opener.
World number four Sinner was left with an uphill battle to save Italy as he faced Djokovic in the singles, with the 36-year-old in stellar form.
Djokovic, who has won seven titles this year including three Grand Slams, was aiming to send 2010 champions Serbia into the final for the first time in a decade.
However Sinner claimed arguably the biggest win of his career, becoming the first man to beat Djokovic in a singles match at the Davis Cup since Argentina's Juan Martin Del Potro in 2011, ending a 21-match streak.
Sinner won the first of their four battles in the ATP Finals group stage, but although Djokovic took the second to bag the title, Sinner delivered twice more in front of a full house at the Martin Carpena arena.
After easing past Cameron Norrie on Thursday, Djokovic created headlines by rowing with noisy British fans and then showing his fury at being asked to take a doping control test before that match.
The Serb was this time unimpressed by rowdy Italian fans in the doubles defeat as he ended a glittering year without the team title he craved.
Subdued Djokovic
Sinner, 14 years the younger at 22, earned the first break in the second singles rubber for a 2-1 lead after Djokovic doubled faulted and then sent a backhand volley into the net.
The Serbian started way below par and Sinner converted the second of two break points with a backhand down-the-line winner and then consolidated to race into a 5-1 lead.
The Italian finished his superb first set with an ace, hitting 12 winners to the subdued Djokovic's one, in only 38 minutes.
With the match seemingly under control he let it slip, double faulting on the first break point he conceded to fall 3-1 behind.
Djokovic ruthlessly capitalised, sealing the set with another break when Sinner whipped a forehand wide.
The Serbian, who has won seven titles this season including three Grand Slams, had the momentum.
Djokovic was on top in the third set with Sinner saving two break points and unable to pressure the Serb's serve.
Sinner appeared to crack in the 10th game, giving up three match points, but then won five consecutive points to hold for 5-5. He then broke Djokovic and held comfortably to triumph.
Italy took the first set of the doubles by breaking Djokovic's serve in the sixth game, as the Serbian duo struggled for a connection.
Both sides exchanged breaks in the second set, with Italy struggling through four Serbia break points to hold for 3-3.
Djokovic responded to crowd noise from Italy between the points, sarcastically encouraging them to make more, before waving his hands like a conductor.
It was Italy who were on song though and Sonego put them a break up for 4-3 with a smash, Serbia's bid ending when Djokovic pushed a Sinner serve into the net.
In the first singles rubber Kecmanovic built on his win over Britain's Jack Draper with another solid display against Musetti, despite losing a nail-biting first set.
Kecmanovic responded strongly in the second set and in full flow, broke twice in the third to rack up a 5-0 lead, winning nine consecutive games on his way to victory.
He swept to victory with a powerful forehand winner, falling to the floor in delight, although by the end of a long day, he was left with the opposite feeling.
