The Australian had his hands full in Thursday's last-16 clash against rising star Alexander Blockx, who'd celebrated his 21st birthday just the day before with the best win of his career, before finally subduing the Belgian qualifier 7-5 7-6 (7-4) on Court des Princes at the Monte-Carlo Country Club.
It thrust de Minaur into the quarters at the prestigious ATP 1000 event which he really enjoys, having also made the semis last year, and helped erase the disappointment of two recent early exits at Indian Wells and Miami.
"It was unfortunate to lose early in the States, because I was actually quite happy with my level and thought I hopefully could go deep," said the world No.6.
"But these things happen, and ultimately, I'm happy I've bounced back here on the clay. Hopefully it's the start of a good clay swing."
It wasn't easy, though, as big-serving world No.91 Blockx, who'd beaten 10th seed Flavio Cobolli 24 hours earlier, raced into an early 4-2 lead, forcing de Minaur to conjure up a couple of breaks to seal the set.
Neither could summon a break in the second stanza, but de Minaur's extra aggression in the tiebreak - he hit 21 winners on the day - helped him wrap up the hard-fought victory in one hour 47 minutes.
In the quarters, 'Demon' will find himself pretty friendless as he faces local Monegasque hero Valentin Vacherot, who beat Hubert Hurkacz 6-7 (4-7) 6-3 6-4.
That continued the fairytale rise which began when, as the world no.204, Vacherot won last year's Shanghai Masters as an alternate qualifier.
"It's still the first week of the clay and there's things I would love to do a little bit better, but, hey, I'm in the quarter-finals, and I'm excited for the battle," said de Minaur.
He'll have even more illustrious company in the last-eight, as Carlos Alcaraz and Jannik Sinner remain on course for a shootout for the world No.1 spot in the final.
Sinner's record run of 37 consecutive sets won at Masters 1000s ended but not his winning streak as the Italian, even while feeling a bit below par after his remarkable 'sunshine double' triumph in the US, finally downed dangerous Czech Tomas Machac 6-1 6-7 (3-7) 6-3.
The Italian knows he'll reclaim the top spot if he beats current No.1 Alcaraz on Sunday, and the Spaniard kept up his part of the bargain by defeating Argentinian Tomas Martin Etcheverry 6-4 4-6 6-3.
Sinner will face sixth seed Felix Auger-Aliassime, who progressed when Casper Ruud was forced to retire with a worrying calf problem as the Canadian led 7-5 2-2, while Alcaraz will play eighth seed Alexander Bublik.
Teenager Joao Fonseca continued his precocious progress, easing past Matteo Berrettini 6-3 6-2 to reach his first Masters 1000 quarter-final at just 19 and set up a mouth-watering clash with third seed Alexander Zverev, who beat Zizou Bergs 6-2 7-5.
