New coach Chris Silverwood celebrated a first ODI series victory with Sri Lanka as his team secured an unassailable 3-1 lead over Australia in Colombo.
It ended Sri Lanka's 30-year wait since their last home triumph in a bilateral ODI series against Australia.
Defeat to Australia in the Ashes scuppered Silverwood's hopes of remaining in charge of England earlier this year, but his new team got the better of the men in yellow on Tuesday.
Replying to Sri Lanka's 258 all out, Australia could only manage 254, losing Matthew Kuhnemann to the last ball of their innings when five runs were required for victory.
Charith Asalanka made a maiden ODI hundred to anchor the home team's innings, reaching 110 before he holed out just inside the deep midwicket boundary, Aaron Finch taking the catch off Pat Cummins' bowling.
Asalanka lived dangerously early on, with a delivery from Cummins seemingly skimming the stumps but not removing the bails; however, he soon found form and hoisted Cummins for six shortly before being the eighth man out. Sri Lanka's main failing was in slumping from 256-7 after 47.3 overs to their final total.
They had recovered well from 34-3, thanks to Asalanka and Dhananjaya de Silva (60) putting on 101 for the fourth wicket, but Australia fancied their task in the chase despite losing captain Finch for a duck in the third over.
The tourists were firmly in the hunt while David Warner remained at the crease, but somebody else needed to step up when the opener fell for 99 to leave Australia 192-7 in the 38th over.
Cummins, the Test captain, accepted the invitation but was pinned lbw for 35 by Chamika Karunaratne late in the 49th over. Kuhnemann made it a desperately difficult final over for Dasun Shanaka, taking 14 from the bowler's first five deliveries; however, the Australia tail-ender hoisted the next delivery high and into the grateful hands of century-maker Asalanka.
Long wait comes to an end
Aravinda de Silva was the star man when Sri Lanka won their three-match home ODI series against Australia in 1992, and it has been three decades of waiting for another such triumph to come around. Now the target for Silverwood will be to deliver performances such as these on a consistent basis.
Now Australia face questions
Sri Lanka made a mess of each end of their batting innings, but the middle order held up. Tuesday's success was a third successive ODI match win over Australia in ODIs, the first time Sri Lanka have achieved that since a three-game streak in February and March 2012.
Australia, who lost 2-1 to Pakistan in April, have lost back-to-back series in the format for the first time since March 2020.