So used to playing in damp and dreary conditions at Roland Garros, Australia's great hope looked energised by the lovely Roland Garros weather on Thursday as he swept into a two-set lead, looking just too fast, too focused and too professional for his eccentric Kazakh opponent.
But it only kicked the world No.62 Bublik into a no-holds-barred, nothing-to-lose boldness as he then stunned the world No.9 with a barrage of brilliant shotmaking to storm back to a 2-6 2-6 6-4 6-3 6-2 victory.
De Minaur had been primed to expect the unexpected from the 27-year-old Bublik but he couldn't have expected the transformation from the player who looked so lost for answers in the opening two sets to the one who then quite dominated for the final three.
It was a crushing blow for the 26-year-old Sydneysider, who had been enjoying his best clay-court season and had looked in the mood to at least try to emulate his breakthrough quarter-final appearance last year.
Bublik is one of the puzzles of world tennis but de Minaur, who'd gone into the match having beaten him three times to nil, looked initially to have solved it perfectly.
The Australian got the full gamut of crazy drop shots, suicidal monster second serves and one inevitable, but dismally executed, underarm delivery from Bublik to start with.
There was the odd dazzling shot - one which sent de Minaur scrambling into the courtside furniture - but, for the most part, Bublik's continual use of the drop shot felt like Einstein's definition of insanity as he played it over and over again only to get the same result as the fastest man in tennis comfortably hunted it down.
But after de Minaur had raced into a two-set lead in just over an hour, it was as if a flick was switched in Bublik's mind. The drop shots were largely jettisoned and a spell of orthodoxy seemed to break out as he began to start using his power superiority to its best effect instead of relying on the dinky, eccentric stuff.
The key was perhaps near the end of the third set when de Minaur had regained equilibrium after going 3-0 down and forged back to 4-4 only for Bublik to go back on the attack and seal the stanza with a brilliant forehand winner.
From then on, de Minaur never really looked composed as Bublik began to show off and get the crowd behind him with some musketeer shotmaking, seen in the point that won him the fourth, which featured a tweener followed by a brilliant backhand bullet down the line. No wonder the Kazakh took a deep bow.
Everything that hadn't been working for Bublik suddenly did and even Paul, de Minaur's faithful young French fan in the crowd, seemed to lose his voice and started looking a picture of misery as the Kazakh raced through the final set, taking his ace count to a dozen.
Then, for his piece de resistance, Bublik finished the job, after de Minaur had saved three match points in the final game, with one rapier-like cross-court backhand winner, his 51st of a marvellously entertaining encounter.
