Australia Day finished as Sri Lanka's night after the tourists pulled off a tense five-wicket win in the first Twenty20 international at ANZ Stadium.
Set 138 to win on a two-paced pitch, Sri Lanka reached Australia's target with seven balls to spare in front of a crowd of just over 40,000.
Thisara Perera (19 not out) brought up the winning runs with consecutive sixes off Ben Laughlin (0-46).
Skipper Angelo Mathews (35 not out) proved the man for the moment, pacing his innings superbly to take the game away from the Australians after Sri Lanka had wobbled at 4-69 in the 11th over.
Openers Kusal Perera (33) and Tillakaratne Dilshan (16) gave the innings early momentum before the tourists fell into a hole.
Spinners Xavier Doherty (2-21), who opened the bowling, and Glenn Maxwell (2-15) took four wickets between them to halt Sri Lanka's progress.
Dilshan was undone by a magnificent diving catch from Laughlin as the home side threatened to take control.
But Mathews' cool hand and Perera's late hitting ensured their side got over the line with something to spare.
Sri Lanka go 1-0 up in the series with the second and final game to be played on Monday at the MCG.
David Warner propped up the Australian innings with a brilliant unbeaten 90, helping set Sri Lanka a modest target.
Wickets fell all around him early but Warner kept his head, combining power hitting with placement to post his highest score in international T20 cricket.
His 90 came off just 62 balls and included five fours and three sixes - the crowd left disappointed the opener couldn't reach 100 as he had promised to deliver a Gangnam Style dance had he reached triple figures.
Adam Voges was happy to play the part of support act, contributing 25 in a partnership worth 84 for the fourth wicket.
Warner's knock should have been stopped in its tracks on 68 when he punched a ball from Mathews (0-39) straight to Nuwan Kulasekara at deep mid-wicket.
But despite the ball coming directly to him at a comfortable height and speed, the Sri Lankan put the simple chance to ground.
Australia got away to a disastrous start, losing Aaron Finch (one) with the score on eight.
The Victorian tried a cute onside push but only succeeded in getting a leading edge to cover where Kusal Perera took a spectacular diving catch.
Shaun Marsh (six) and George Bailey (11) made little impact before Voges joined Warner in an enterprising partnership.
Lasith Malinga (0-19 from four overs) was again the pick of the bowlers, failing to take a wicket but proving almost impossible to get away.
The Sri Lankan batsmen did the rest, albeit not without a few anxious moments.