'Demon' fought admirably to halt his run against the ruthless world No.2 in Saturday's semi-final, yet there was still a sinking sense of inevitability that the title holder would make it an unlucky-13 wins in a row over the great Aussie trier at the Inalpi Arena with another ruthless 7-5 6-2 demolition job.
Cheered on by 13,000 adoring home fans, Sinner had to overcome the most doughty first-set resistance from the Aussie until forging away in breathtaking fashion to set up a final against world No.1 Carlos Alcaraz.
Yet after a crucial week in de Minaur's still improving career, marked by his first ever win at the season-ending championship over Taylor Fritz, he was not about to feel as wholly dejected as earlier in the week when he berated himself for blowing a glorious chance to beat Lorenzo Musetti.
For, despite Sinner making it 29-2 in their overall sets-score in the most one-sided rivalry that now exists at the top of the men's game, de Minaur insisted: "I'm in a much better place.
"I think today there was a lot of good stuff. Ultimately, we've just got to keep on improving. There's no other way."
And reflecting on Sinner's latest masterclass, which would have confounded every opponent apart from perhaps Alcaraz, he could smile: "I know how to beat him ... it's just not that easy to do, right?"
Too right. For 'Demon' tried everything, playing almost as well as could be hoped in a 66-minute opening set.
Yet when his first-serve percentage dropped in the second, the Wimbledon and Australian Open champ pounced, roaring into a third-straight final with what de Minaur admitted felt like "constant pressure".
The world No.7 earned three break points in Sinner's opening service game, but the man who's now won 30 consecutive indoor hardcourt matches escaped and never gave de Minaur another sniff.
"To beat him, you've got to hit the ball very hard, very flat, very deep and very close to the lines. It's obviously not the easiest thing to do. I need to serve well throughout the whole match, but my serve dropped a little and could have been better," de Minaur shrugged.
He saved seven break points in that opening stanza under the most suffocating pressure, until Sinner finally cracked him with a rapier backhand winner to move 6-5 up.
But Sinner moved inexorably into another gear in the second set, earning an immediate break with an astonishing down-the-line sliding backhand and then racing into a 4-0 lead while conceding just five points.
De Minaur was being totally outplayed, only not in the heart department, as he reduced the deficit to 1-4 to huge sympathetic applause from the locals.
But Sinner was irresistible, leaving de Minaur to offer an imploring look up at his players' box as if to ask 'what can I do?'.
With his 30th winner, a searing inside-out forehand, Sinner sealed his 14th consecutive victory on his end-of-season tear before paying tribute to his valiant opponent.
"It was a tough match," he admitted. "I felt like he was serving great, very precise. In the second set, I broke very early and then my level rose. I tried to be a bit more aggressive and it worked well."
In the other semi-final, top-ranked Alcaraz beat Felix Auger-Aliassime 6-2, 6-4 to finish the week 4-0.
It's Alcaraz's third time at the Finals, although he withdrew from his first appearance in 2022 due to injury.
He led Auger-Aliassime 25-15 in winners and committed half as many unforced errors as his Canadian opponent, 10-20. The Spaniard called it his best performance of the tournament.
"I'm really happy with the level today," Alcaraz said. "I played really solid, really aggressively," he said.
Auger-Aliassime beat Ben Shelton and Zverev in the group stage after losing to Sinner, and will finish the year at a career-high No. 5 after a strong indoor season.
