Sinner made it three from three in Austria since retiring injured from the Shanghai Masters earlier this month with a 6-4, 6-4 win over the eighth-seeded Russian-born Kazakh.
Sinner, seeking his fourth title of 2025, will face third seed Alex de Minaur in the last four after the Australian beat Matteo Berrettini 6-1, 7-6(4) in his last eight test.
Four-time Grand Slam champion Sinner said: "It is a tough, tough matchup. I am very happy.
"I tried to return as many balls as possible. I felt he was serving great today.
"He is a very dangerous player, but I tried to stay as solid as possible, so I am very happy."