Australia's No.2 Duckworth, who reached the semi-final last year and the final of the indoor hard-court final back in 2021 when it was held in Astana, had high hopes of making the last-four again as he lined up against the Greek two-time grand slam finalist on Friday.
But after a lean spell when his ranking plummeted amid his back injury woes, a dip in confidence and off-court distractions, Tsitsipas has begun to look more like his old self of late and was in no mood to let the world No.73 halt his revival as he won their quarter-final with a clinical display, 6-3 6-4.
Serving down 15 aces and executing 33 winners, the Greek world No.39 reached his 56th tour semi-final without giving up a single break-point opportunity, leaving Duckworth's hopes of a fifth tour semi-final appearance always looking forlorn.
Tsitsipas, who meets Georgian Nikoloz Basilashvili in the semi-finals, is on a collision course to face top seed Daniil Medvedev in the final, just a week and a half after the Russian beat him at the Shanghai Masters.
First, though, defending Almaty champ Medvedev, who beat Frenchman Terence Atmane 6-4 6-4 on Friday, has to get past third seed Alexander Bublik in the semis.
And Medvedev's win wasn't good news for Alex de Minaur in the Australian No.1's ongoing quest to reach the ATP Finals on a day when a couple of other contenders to get to the season-ending men's championship were also racking up crucial qualifying points in European tournaments.
De Minaur, whose 2880 points currently puts him ninth in the list of players all vying for just eight places in the Finals, is having a week off from competitive action.
Meanwhile, Medvedev has taken his points tally in fifth to 3510 while fourth-placed Flavio Cobolli has gone on to 3590 by reaching the last-16 in Lyon and seventh-placed Arthur Fils has extended his total to 3375 by making the Brussels quarter-finals.
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