Sri Lanka downed Australia by five wickets to win the opening T20 international at the Sydney Olympic Stadium on Saturday.
Two towering sixes on consecutive balls from Sri Lanka's Thisara Perera sealed a comfortable win for the visitors, who have now beaten Australia in their last four T20s.
The win was set up by some superb bowling from Sri Lankan pair Lasith Malinga and Nuwan Kulasekara, who earlier restricted the Australians to 137-3 from their 20 overs.
The Sri Lankans reached the target with seven balls to spare and are now guaranteed of retaining their number one ranking regardless of what happens in the second and final match in Melbourne on Monday.
Australia earlier won the toss and chose to bat, but apart from big-hitting opener David Warner they found scoring difficult.
The Sri Lankans always had the target well in hand, once openers Kushal Perera (33) and Tillakaratne Dilshan (16) put on 46 runs in 38 balls for the opening wicket.
SCORES IN BRIEF
AUSTRALIA: 137 for 3 in 20 overs (Warner 90 not out, Voges 25 not out; Kulasekara 1-21, Perera 1-29)
SRI LANKA: 139 for 5 in 18.5 overs (K Perera 33, Dilshan 16, Mathews 35 not out, Thirimanne 20, T Perera not out 19; Doherty 2-21, Maxwell 2-15)
Result: Sri Lanka won by five wickets.
Player-of-the-match: David Warner.