Chasing a moderate 128 for victory, the Aussies were restricted to 117/4 in their 20 overs as the Tigers sealed the series with two games to go
Bangladesh beat Australia by 10 runs to take an unassailable 3-0 lead in the five-match T20I series at Mirpur Sher-e-Bangla National Cricket Stadium Friday.
Chasing a moderate 128 for victory, the Aussies were restricted to 117/4 in their 20 overs as the Tigers sealed the series with two games to go.
Mitchell Marsh top-scored with a 47-ball 51, and shared a vital 63-run stand for the second wicket with Ben McDermott (35), but the visiting side lost their way from there to fall short by 10 runs.
Left-arm seamer Shariful Islam took two wickets.
Earlier, Australia seamer Nathan Ellis bagged a hat-trick on debut, becoming the first ever cricketer to do so in T20Is, as Bangladesh were restricted to 127/9 in their 20 overs.
Ellis first cleaned up Bangladesh captain Mahmudullah, who top-scored with 52 off 53 balls, before both Mustafizur Rahman and Mahedi Hasan were caught in the deep off consecutive deliveries to complete the hat-trick.
Ellis was supported well by Josh Hazlewood and Adam Zampa who picked up two wickets each.
Mahmudullah had won the toss and decided to bat first.
The toss was delayed by an hour and a half due to rain, but there will be the full complement of 20 overs, while the innings break will consist of 10 minutes.
The Tigers, leading 2-0, will be looking to wrap up the series Friday with two games to spare, while the Aussies will be desperate for victory to stay alive in the series.
Bangladesh are unchanged from the second T20I, while Australia made three changes with McDermott, Ellis and Dan Christian coming in for Josh Philippe, Mitchell Starc and Andrew Tye.
Mohammad Naim, Soumya Sarkar, Shakib al Hasan, Mahedi Hasan, Mahmudullah (capt), Afif Hossain, Shamim Hossain, Nurul Hasan (wk), Nasum Ahmed, Mustafizur Rahman, Shariful Islam
Matthew Wade (capt & wk), Ben McDermott, Mitchell Marsh, Moises Henriques, Alex Carey, Ashton Turner, Dan Christian, Ashton Agar, Nathan Ellis, Adam Zampa, Josh Hazlewood