Right-arm pacer Nuwan Kulasekara [ Images ] claimed a career-best five for 22 as Sri Lanka skittled Australia for just 74.
A brave effort from Australia's bowlers was not enough to make up for a disastrous start their batsman after they elected to bat.
Kulasekara tormented the right-handers with his in-swinging deliveries while Lasith Malinga [ Images ] (3-14) polished off the tail as Australia collapsed in 26.4 overs with only Mitchell Starc (22 not out) and Xavier Doherty (15) managing double digits.
Number nine Starc took a couple of blows on his helmet but hung on to take Australia past their previous lowest total of 70 that came on two occasions, against England [ Images ] in Birmingham in 1977 and New Zealand [ Images ] at Adelaide in 1986.
Angelo Mathews [ Images ] drew first blood with the seventh delivery when he removed opener David Warner and Australia captain Michael Clarke [ Images ] was soon left to rue his decision to bat first at the Gabba [ Images ] as the batting order came unstuck.
Kulasekara was on a hat-trick after removing David Hussey [ Images ] and George Bailey off successive deliveries but Matthew Wade denied him the personal milestone.
That was hardly solace for the hosts as the 30-year-old bowler returned to peg back Clarke's middle stump and push one through Moises Henriques's gate for his first five-wicket haul.
Sri Lanka wobbled early in their chase before reaching 75 for six in 20 overs.
Kushal Perera top-scored for the tourists with an unbeaten 22, while Tillakaratne Dishan also contributed as many runs.
Mitchell Johnson was the most successful Australian bowler, claiming three for 11.
Sydney [ Images ] hosts the fourth one-dayer on Sunday.
Sri Lanka leads the five-match series 2-1.Photograph: Robert Cianflone/Getty Images