World No.6 de Minaur, watched by his mum in his player's box at the Monte Carlo Country Club on Friday, saw another big opportunity evaporate as he eventually succumbed 6-4 3-6 6-3 against the sport's 'Cinderalla man' Vacherot, the Monegasque who's risen spectacularly from nowhere over the past six months.
It felt like one of those near-misses that 'Demon' berated himself for last season as he looked to have weathered a storm from the powerful Vacherot and gradually wore him down, only for the weary 27-year-old to summon one last blistering salvo to down the game Australian after an absorbing two hours and 24 minutes.
The crowd at Vacherot's home club, including family and scores of old friends, cheered him to the rafters as he finally overcame the typically resilient de Minaur, who even saved two match points with audacious drop shots in the final game before succumbing to an unstoppable forehand service-return winner.
Extraordinarily, it meant that the last-four in Monte Carlo will feature the world's top three - Carlos Alcaraz, Jannik Sinner and Alexander Zverev - plus Vacherot, the man who this time last year was No.285 in the world.
"That sounds amazing - such an honour for me to be along with the best three players of the last few years. To play Carlos in the semi-final in my home is amazing," said Vacherot, whose stunning rise began in October's Shanghai Masters when, as an alternate qualifier, he won as the world No.204.
It's a dream semi for the organisers but the likelihood is that there'll be a Jannik Sinner-Alcaraz final, which would be the big two's first duel on clay since last year's epic French Open showdown - won by the Spaniard - and would also be a showdown to decide who'll be No.1 in the world.
Current top dog Alcaraz was merciless in disposing of Alexander Bublik 6-3 6-0 for the 300th tour-level victory of his career in just his 367th match. In the Open era, only Australian legend Rod Laver (355 matches) and American great Jimmy Connors (363) got to the landmark faster.Â
Meanwhile, Sinner became just the fourth player to rack up 20-successive Masters 1000 wins by beating Felix Auger-Aliassime 6-3 6-4.
Sinner follows the great trio of Roger Federer, Rafael Nadal and Novak Djokovic in achieving the 20-wins-in-a-row landmark.
World No.2 Sinner will face Alexander Zverev in the semi-finals, after the German had to summon up his best to subdue the precocious talent of 19-year-old Brazilian Joao Fonseca 7-5 6-7 (3-7) 6-3.
