Australia's impressive No.1 had to subdue a second-set rally from Matteo Berrettini before putting away the former Wimbledon finalist a mite nervously 6-1 7-6 (7-4) in their quarter-final at the Wiener Stadthall on Friday.
The victory, which de Minaur was just a little relieved to finally nail down after Berrettini had saved three match points, put the tireless Sydneysider into his 30th tour-level semi-final while strengthening his bid to make the end-of-season ATP Finals again.
But whether he'll go any further is the big question as his next assignment will be to beat Sinner for the first time after the world No.2 disposed of dangerman Alexander Bublik 6-4 6-4.
Asked on court if he was physically and mentally ready for the battles ahead, de Minaur just smiled: "I'm always ready, mate. I stay ready.
"I'm pleased with with my level so far. I played some some great tennis for about three quarters of that match. I'm gonna have to keep that level going forward."
Sinner has beaten de Minaur in all 11 meetings, with the chink of light for the Aussie being that he at least managed to win his first set in five years off the Australian Open and Wimbledon champ in their latest clash in Beijing last month.
Sinner just ignores the stats. "Alex is playing some great tennis. It was close in Beijing and it's going to be a tough, physical test," said the Italian, who looked rock-solid in his 19th successive indoor hard-court victory.
But de Minaur is looking fresh and sharp, playing excellently for the most part against Berrettini who, despite having won three of their four previous clashes, couldn't live with his speed and agility this time.
Berrettini, who's had so many injury struggles of late, was stunned by the Aussie's unerring quality of return, as he powered into a 5-0 lead before the world No.59 could even get on the board.
De Minaur's level did drop, as Berrettini's power enabled him to break back twice in the second set, the second coming after he'd survived a match point when serving at 5-3 down.
De Minaur was mad to miss "an unmissable" backhand volley at the net that should have given him another match point but only allowed Berrettini an escape route back to 5-5.
In the tiebreak, de Minaur dominated for a 6-2 lead, but squandered another couple of match points before finally getting the job done with his 21st winner, a volley, to become the first man this year to 40 hard-court wins.
But even if 33 unforced errors won't cut it against Sinner, at least de Minaur's place in the eight-man ATP Finals in Turin looks increasingly assured.
Seventh in the standings, not only did he move to within a victory of leapfrogging Ben Shelton into sixth but, with ninth-placed Felix Auger-Aliassime having had to pull out with injury when a set down to Jaume Munar in Friday's Swiss Indoors quarter-final in Basel, 'Demon's' chasers are struggling.
Meanwhile, Alexander Zverev booked his place in Turin alongside Carlos Alcaraz, Sinner and Novak Djokovic after his Vienna quarter-final opponent Tallon Griekspoor withdrew injured.
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