Italy returned to the Davis Cup final after a gap of 25 years as Jannik Sinner beat Novak Djokovic in both singles and doubles to secure a 2-1 victory over Serbia on Saturday that earned the 1976 champions a title clash with Australia.

Sinner and doubles partner Lorenzo Sonego beat the Serbian duo of Djokovic and Miomir Kecmanovic 6-3 6-4 to secure a famous victory that sent the former champions packing and sparked wild celebrations at a heaving Martin Carpena Arena in Spain.

Up next for Filippo Volandri's side, who will be playing in an eighth final and seeking a second trophy, are 28-times champions Australia after Lleyton Hewitt's team eased past giant-killers Finland on Friday.

Sinner earlier saved three matchpoints to stun Djokovic 6-2 2-6 7-5 in an extraordinary singles match to help Italy draw level with Serbia at 1-1 after Kecmanovic had put the 2010 champions ahead by beating Lorenzo Musetti 6-7(7) 6-2 6-1.

Sinner was facing Djokovic for the third time in 11 days and the world number four, who beat the top-ranked Serbian early in the ATP Finals before losing to him in the title clash, made a quick start to ease through the opening set with two breaks.

The 22-year-old, who had sparked Italy's comeback in their quarter-final against the Netherlands, took his foot off the gas in the next set to allow Djokovic back in but kept chipping away in the hope of sealing a second win over him in six meetings.

He saved three matchpoints from 0-40 at 4-5 in the decider and then broke Djokovic for a 6-5 lead before holding his nerve to make a forehand pass and pull off one of the most remarkable wins of his career amid deafening cheers.

"It was for sure the game-changer today," Sinner said of his singles heroics at 4-5. "I just tried to push in every single point and the 0-40 game helped the confidence and also after I broke him. It's all part of tennis.

"Obviously playing doubles in the decider of a Davis Cup tie is not easy. There's a lot of pressure, I think we both handled it really well. We are a very complete team and each one of us is really happy to be here.

"Tomorrow we'll try our best. Let's see what's coming." (Reuters)