The Australian No.1, a picture of despair just a couple of nights earlier after feeling he'd thrown away victory during defeat to Lorenzo Musetti, started his unlikely resurrection with a backs-to-the-wall 7-6 (7-3) 6-3 win over Taylor Fritz on Thursday, his first ever victory at the season-ending championship.
Then after achieving the two-sets-to-nil triumph - the only way he could stay in the tournament - de Minaur owed a huge vote of thanks to Carlos Alcaraz, who sealed the end-of-season world No.1 ranking by beating home favourite Musetti 6-4 6-1.
"I mean, sport," de Minaur smiled, even before the Alcaraz match. "Couple of days ago was one of the toughest days I've had in my career. I was in a very, very dark spot.
"I could tell you that I hated the sport. Now here we are two days later, and I'm feeling great about myself. It's incredible."
So, against all odds, 'Demon' finished second behind Alcaraz in the Jimmy Connors Group, qualifying for the semi-finals. He's only the third Australian ever to do so after John Newcombe (1973-74) and Lleyton Hewitt, the 2001 and 2002 winner and 2004 finalist.
That had looked totally improbable after world No.7 de Minaur had been left completely dejected, losing after serving for the match against weary home favourite Musetti on Tuesday at the Inalpi Arena.
At his post-match news conference, admitting that losing matches he felt he should have won was "getting to a point where mentally it's killing me", he added if he didn't get it sorted, "it's going to eat me alive".
So on Thursday, with a sympathetic crowd right behind him, the 26-year-old may have pulled off the most important win of his career, downing big-serving world No.6 Fritz.
For even if he gets no further - he's likely to face his nemesis and home hero Jannik Sinner in the semi-finals - this was a vital confidence-booster to remind himself he can get the job done against the elite.
Not that it came easy. De Minaur was 4-4 and down 0-30 on his serve in the opening set, with Fritz threatening to win the stanza which would have knocked him out.
Instead, de Minaur took that game, dominated with a brilliant tiebreak and then controlled a largely one-sided second set to finally win a Finals match at the sixth attempt, after going winless on debut last year and then losing to Alcaraz and Musetti this week.
After his one-hour 34-minute win, de Minaur looked to the heavens and shook his hands in joy before scrawling on the courtside TV camera lens "Finally" alongside a smiley emoji.
"I've dealt with a fair bit of heartbreak recently. It was good to - finally - get a win," he sighed.
"More than anything, regardless of the result today, I had made peace with myself. I was okay with the result not going my way. I just wanted to play my way. It felt good to play on my terms.
"I was gonna leave everything out there and I ended up with a really good match from the start 'til the end. It was good to get some positive reward for that hard work."
De Minaur reckoned he was "incredibly lucky to have the support system that I have", giving a special mention to fiancee, Katie Boulter, who'd cheered him on at courtside.
When told by his interviewer that he would make the last four if Alcaraz beat Musetti, he said: "Is that actually true or not? I don't know. I don't trust you right now.
"Whatever happens, happens, but I won't be paying too much attention to the tennis. I'll be relaxing and having a nice night here in Torino."
And how nice it turned out to be as Alcaraz, looking ominously good, completed his third consummate victory of the week in just 83 minutes to become a two-time year-ending world No.1.
"I had to handle my nerves the best I could and I was happy the way I did it," said the Spaniard, who's had an incredible year with eight titles and two grand slam titles in Paris and New York.
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