The triumph carried special significance for the Tigers. Before Monday's victory, Bangladesh's only ODI win over Australia had come in the famous 2005 Cardiff upset, when a young Mohammad Ashraful announced himself on the world stage with a match-winning century.
More than two decades later, Ashraful watched from the dugout as Bangladesh's batting coach as the Tigers once again stunned Australia.
The match was also the first men's bilateral ODI meeting between the two nations in 15 years.
After being asked to bat first, Bangladesh posted a competitive 284 for 8, built around half-centuries from Najmul Hossain Shanto, Tanzid Hasan and Musaddek Hossain.
Tanzid provided early momentum with a brisk 54 off 44 balls, while Shanto anchored the innings with a composed 67 from 86 deliveries.
After Bangladesh slipped from 106 for 1 to 140 for 4, Musaddek produced a superb counterattacking innings on his return to the national side, remaining unbeaten on 86 from just 70 balls, including seven fours and three sixes.
Towhid Hridoy added 31, while Taskin Ahmed's late cameo of 20 helped Bangladesh accelerate in the closing overs and finish with a challenging total.
Nathan Ellis was Australia's best bowler, claiming 3 for 38, while Liam Scott and Matt Renshaw picked up two wickets apiece.
Australia's chase got off to the worst possible start when Matthew Short was bowled by Taskin Ahmed with the very first ball of the innings. The visitors then lost Marnus Labuschagne for just one as Bangladesh's pace attack seized control.
Cooper Connolly (35) and Alex Carey (47) attempted to rebuild, but the turning point came through Nahid Rana.
The young fast bowler produced a sensational spell, dismissing captain Josh Inglis, Carey, Liam Scott and Xavier Bartlett to finish with career-defining figures of 4 for 41.
Mustafizur Rahman chipped in with two wickets, while Musaddek capped a memorable all-round performance by taking 2 for 37. Australia slumped from 128 for 4 to 156 for 9 as Bangladesh tightened their grip on the contest.
Cameron Green fought a lone battle with an unbeaten 52, but rain eventually brought an early end to proceedings with Australia on 191 for 9 after 42.2 overs.
Bangladesh were comfortably ahead on the DLS calculations and were declared winners by 86 runs.
The result continues Bangladesh's impressive recent record at home and gives them a golden opportunity to secure a rare ODI series victory over Australia.
For Nahid, meanwhile, it was another statement performance against elite opposition, underlining why he is regarded as one of the brightest fast-bowling prospects in world cricket.
Bangladesh now lead the three-match series 1-0 heading into the second ODI in Mirpur.
