The Australian was in merciless mood against the out-of-sorts veteran, taking only 44 minutes to hand the world No.18 one of his most embarrassing defeats on the Monte Carlo Country Club's main arena, Court Rainier III, on Friday.
It was a real statement performance from 26-year-old de Minaur, as he reached the third clay-court semi-final of his career and demonstrated that this is no longer a surface that befuddles him.
Asked if he realised he had achieved the first whitewash win of his pro career, de Minaur smiled: "I did know that - and I also know the only time I ever lost 6-0 6-0 myself was to Tommy Paul in the semi-finals of the US Juniors. It's pretty crazy!"
A 'double bagel' is certainly a rare feat at this level of tennis. Indeed, it was the first such scoreline in any ATP tournament at the quarter-final stage and beyond for 12 years since the great Roger Federer blanked Mischa Zverev in the last-eight in Halle.
World No.10 de Minaur had expected a tough duel against the evergreen Dimitrov but after dominating the early stages, seemed to drain all the belief and confidence out of the 33-year-old and then never took his foot off the pedal as the Bulgarian just coughed up more unforced errors, 23 in all.
After winning the first set 6-0 in just 23 minutes - the first time Dimitrov has failed to win a game in any stanza for nine years - de Minaur earned another break at the start of the second with a dazzling backhand lob that just continued the strangulation.
Getting only stronger and more aggressive as the one-sided fare progressed, de Minaur dropped only 15 out of the 63 points played to become the first Australian since John Alexander in 1979 to make the semi-finals of the famous old tournament in the Principality.
He's also the first Aussie since Lleyton Hewitt in Hamburg in 2007 to reach a Masters 1000 clay-court semi-final as he chalked up a tour-leading 20th win of the season.
There was even better news for de Minaur as he pondered the chance of reaching his first clay-court final as he won't be facing his nemesis Stefanos Tsitsipas in the last-four, with Italian Lorenzo Musetti causing an upset by defeating the Greek 1-6 6-3 6-4.
Tsitsipas, who had a woeful day with his serving, holds an 11-1 career record against de Minaur, but the Australian has a 1-1 record against the Wimbledon semi-finalist Musetti in what looks a difficult match to call as they meet for the first time on clay.
Earlier, the rare treat of two Australians making the semis of the same Masters event was dashed when Alexei Popyrin was soundly beaten 6-3 6-2 by Spain's Alejandro Davidovich Fokina in 69 minutes.
So frustrated was Popyrin by his off-day after winning three matches in three days, he ended up getting a code violation for ball abuse, trying to smash one out of the stadium in anger.
Match of the day, though, featured Carlos Alcaraz's fabulous, hard-fought victory over young French gun Arthur Fils, the 20-year-old rising talent who will be ruing his missed opportunities after going down 4-6 7-5 6-3 in a thrilling contest on Rainier.
"I have missed clay," beamed the French Open champ.
