Sri Lanka spoiled Australia Day celebrations in Sydney with a five-wicket win in the opening Twenty20 International of the series.
Having restricted Australia to 137-3, despite David Warner hitting an unbeaten 90, the tourists successfully chased down their target with seven balls to spare at Stadium Australia.
Kushal Perera gave them a good start with a breezy 33 at the top of the order, even being the more aggressive partner in an opening stand of 46 with Tillakaratne Dilshan (16).
However it was namesake Thishara Perera who rushed the Sri Lankans over the line. Just as it seemed all set up for a tense finish, the left-hander belted Ben Laughlin for back-to-back sixes to finish the game in a flash.
Skipper Angelo Mathews was at the other end unbeaten 35, his efforts with the bat making amends for his bowling earlier in the day that had seen his four overs leak 39 runs.
The rest of Sri Lanka's attack, however, faired much better. Nuwan Kulasekara continued his good form from the drawn one-day series with 1-21, picking up the early wicket of Aaron Finch thanks to a diving catch by Kushal Perera.
Lasith Malinga conceded just 19 in his spell and the bowlers' efforts were backed up in the field; Dilshan ran out Shaun Marsh for six before clinging on to a chance from home skipper George Bailey (11), leaving the score at 53-3.
Indeed, had it not been for Warner, Australia may have only just reached three figures. The left-handed opener - who plays for the Sydney Thunder in the domestic Big Bash - belted five fours and three sixes in his 62-ball knock.
Adam Voges chipped in with 25 not out during an unbroken stand of 84, though the hosts always looked to be a little light at the halfway stage.
Australia will look to level the two-match series in Melbourne on Monday, live on Sky Sports.