Australia have reason to reconsider their bowling make up ahead of next year's one-day World Cup after being asked to pull off their biggest ever successful chase against Sri Lanka.
Sri Lankan star Kusal Mendis hit an unbeaten 86 from 87 balls in Tuesday's opener to the five-match series, as the hosts posted 7-300 batting first in Pallekele.
David Warner provided the main highlight for Australia, taking a brilliant back-handed catch while leaping high at mid-on to remove opener Pathum Nissanka.
But questions remain over the make-up of Australia's bowling attack and preference to play three frontline quicks ahead of next year's World Cup in India.
On a slow wicket that offered little for the pacemen, Australia opted not to play Mitchell Swepson with chief spinner Adam Zampa back home on paternity leave.
Ashton Agar (2-49) and Glenn Maxwell (0-60) both sent down 10 overs each, while part-time leggie Marnus Labuschagne (2-19 off 3) was also called upon late.
In comparison Australia's trio of quicks in Josh Hazlewood, Pat Cummins and Jhye Richardson went for a combined 1-166 from their 26 overs.
Despite that Australia did well to contain Sri Lanka after the hosts put on a 115-run opening stand that almost came at a run a ball.
Danushka Gunathilaka in particular was damaging, hitting seven fours in his 55 from 53 balls.
His most powerful came off Hazlewood, planting his foot and taking the seamer from outside off-stump to the mid-wicket boundary with one bounce.
But Sri Lanka's momentum slowed off a poor piece of running from the left-hander, after he hit Agar towards the legside rope.
After jogging the first, he was caught marginally short by a perfect over-the-stumps throw from Marcus Stoinis.
Gunathilaka's opening partner Pathum Nissanka and first-drop Dhananaya then followed.
And while Dhananaya was the victim of Warner's brilliance, Nissanka threw his wicket away with a wasteful reverse sweep off Agar on 56.
Mendis then took charge.
With the slow wicket hard to score off in the middle overs, he was lucky to survive a tough chance from Labuschagne on the boundary on 17 and a near run out on 22.
But he rode his luck, hitting eight boundaries and smashing the biggest six of the day when he charged down the wicket at Maxwell and put him over cow corner.
Wanindu Hasaranga also finished with 37 from 19, taking 22 from the penultimate over from Richardson as he repeatedly guided him behind square on the offside.
Australia have never chased down more than 267 against Sri Lanka, but are close to full strength with the bat with Warner, Steve Smith and Maxwell playing their first ODIs in 18 months.
There was one other concern for Australia with Agar spending the end of the innings off the field with a sore side after his 10-over spell.