Australia faces a significant challenge to continue their winning start to the Commonwealth Bank Series after being bowled out for 231 against Sri Lanka at the WACA Ground on Friday.
A top order collapse saw the hosts slump to 4-81 in the 19th over of their innings and they couldn't recover to post a strong score despite decent contributions from Michael Clarke (57 off 88) and Daniel Christian (33 off 44).
Tailenders Clint McKay (25 off 25) and Mitchell Starc (14 off 19) put on a 32-run ninth wicket partnership to help rescue some hope for Australia from a dire situation at 8-192, but Clarke's side was still dismissed with five balls remaining.
Sri Lanka will still have to score at just 4.64 runs per over to reach their target of 232 and earn their first win of the one-day international tri-series.
Angelo Mathews and Nuwan Kulasekara were the most impressive bowlers for the visitors, taking 2-37 off nine overs and 2-39 off 10 respectively in tight displays.
Lasith Malinga (2-46) and young spinner Sachithra Senanayake (2-45) also bowled well for Sri Lanka, who have won just two of their 16 ODIs at the WACA.
David Warner started Australia's innings with a quick-fire 34 off 29 balls but the rest of the top order failed after they were sent in to bat in the blistering Perth heat.
Matthew Wade and Ricky Ponting were both dismissed for one in the first five overs before Warner chopped a Mathews delivery onto his stumps and Michael Hussey (23 off 32) fell to a spectacular Kulasekara catch off his own bowling.
That left Australia, who beat India in their first match of the series, needing a big middle-order effort to post a competitive score and Clarke and David Hussey (27) momentarily stabilised their innings.
They put on a 49-run fifth-wicket partnership but again the situation worsened when the younger Hussey brother hit a Malinga delivery with a leading edge to short extra cover.
And things could have been even more precarious for Australia had Clarke not survived two strong lbw appeals in Dhammika Prasad's next over.
Christian smashed three consecutive fours off one Prasad in an early sign of his intent and he built a 56-run stand with Clarke before the all-rounder was stumped off Senanayake.
Clarke was then furious with himself when he played a full Mathews ball straight to mid-wicket and when Ryan Harris was out for three Australia had lost three wickets in three overs.
But McKay and Starc frustrated Sri Lanka with their late big hitting before both were caught in the deep in the final overs.