The world number four clinched victory in the second singles rubber after Matteo Arnaldi dug deep to beat Alexei Popyrin 7-5, 2-6, 6-4 in the opening clash.
Sinner, who remarkably beat top-ranked superstar, Novak Djokovic, twice in one day on Saturday, as Italy eliminated Serbia, secured his country’s second title against Lleyton Hewitt’s 28-time winners in style.
The Italian demoralised the scampering De Minaur with a relentless performance, overpowering him with vicious ground strokes.
Sinner had won each of the five prior meetings between the pair and the world number 12 came no closer this time, brutally dismantled in under 90 minutes.
Australia’s wait for a Davis Cup trophy goes on, with their last coming in 2003, but Italy, who last reached a final in 1998, celebrated wildly when De Minaur went wide to end the tie.
Sinner, laser-focused from the start, broke early in the first set for a 2-1 lead when De Minaur sent a lob long and then consolidated with a powerful forehand.
The 22-year-old brought up three set points and clinched the first set with the second of them when De Minaur volleyed beyond the baseline.
In the second set, Sinner produced 19 winners with just five unforced errors to sweep to victory.
Arnaldi had to cling on to beat Popyrin in the first match.
“I think I won one of the most important matches in my life, I don’t know what to say right now,” said an emotional Arnaldi.
Australia captain Hewitt opted to maintain Popyrin in the first singles rubber, while Italy’s Filippo Volandri returned to Arnaldi ahead of Lorenzo Musetti, despite his defeat in Italy’s 2-1 quarter-final win over the Netherlands.
Popyrin, whose nerves were jangling in the semi-final singles first set against Finland, started his first service game with a double fault after Arnaldi held to love.
Arnaldi brought up three break points the next time with a fizzing forehand and took the third of them when Popyrin went long, for a 3-1 lead.
However world number 40 Popyrin reacted immediately by breaking back and holding, both to love, showing he would not be overawed by the occasion.
Arnaldi earned three set points but the Australian rescued them and completed a tough hold for 5-5 with two strong serves.
Popyrin wasted two break points as Arnaldi held for 6-5 and then pushed a return into the net to hand the Italian a tense first set.
The Australian was far stronger in the second set against Finland and it proved the case again, as he raced into a double break against Arnaldi, saving a break point as he held for 4-0.
Arnaldi finally got on the board in the fifth game but Popyrin — who produced six aces in the second set to the Italian’s zero — served it out to force a decisive third set.
The erratic Arnaldi saved break points in his first, second and fourth service games without putting pressure on Popyrin’s serve until earning a break point which the 24-year-old saved, holding for 4-4.
Popyrin was on top but could not make it count to get the breakthrough, with Arnaldi saving another break point on his way to a 5-4 lead.
Despite being outplayed for the best part of the third set Arnaldi converted his first set point to put Italy ahead in the tie with a powerful forehand, with Sinner completing the job without a fuss.
AFP
