TURIN, Italy (AFP) — Jannik Sinner edged towards becoming the first ever Italian to reach the Last Four of the ATP Finals on Tuesday after a thrilling 7-5, 6-7 (5/7), 7-6 (7/2) win over Novak Djokovic.

World No. 4 Sinner needed a straight-sets victory in front of enthusiastic home support in Turin over tennis icon Djokovic to guarantee passage from the Green Group with a match to spare.

And while the 22-year-old couldn't quite make that happen, a superb performance gave him his first win in four attempts over Djokovic, who is bidding to win for a record seventh time at the year-ending tournament.

"It means a lot to me," Sinner said in court.

"When you win against the world No. 1 who has won 24 Grand Slams it's obviously in the top-top."

Fans made an almighty din for Sinner, chanting his name to the rafters once he claimed victory in an exciting, three-hour contest which ran way past midnight at the Pala Alpitour.

Sinner has had the best year of his career and looks to be fulfilling the promise he has long shown, winning four titles this season including the Masters 1000 event at Toronto, and looks on form in Italy.

He made the first breakthrough when he capitalized on Djokovic handing him advantage in game 11 with a double fault, moving 6-5 ahead with a big backhand before claiming the set with a service game to love.

Djokovic pulled level after a bruising second set in which neither player faced a single break point, but after fighting back from 4-2 down in the decider he wilted in the tie-break and ended his winning run at 20 matches.

"In these kinds of matches, very few opportunities will be presented and if you don't use them then the other player will," Djokovic said.

"Some you win, some you lose. I don't think I've done too many things wrong in terms of my game, he was just more decisive and courageous in the moments where he needed to be."

Both players' fate will be decided in the final round of group matches, with Djokovic facing Hubert Hurkacz who has stepped in for Stefanos Tsitsipas after the Greek pulled out of the tournament with a back injury against Sinner's next opponent Holger Rune.