However it was former skipper George Bailey who guided the visitors to victory, compiling a composed 70 from 99 balls as the Aussies scampered to a two-wicket win in Dambulla to take a 2-1 lead in the five-match series.
The rise in the ranks did little to improve Warner’s struggling form as he was dismissed for 10 in the chase of 227.
But Bailey was impressed by the opening batmen’s first game in charge after Steve Smith was sent home for an early rest.
“I think he’s a natural leader,” Bailey said.
“The conversations I was privy to when he was talking to the bowlers, he was very clear and direct.
“He keeps things simple – they’re all pretty good things to have as a skipper.”
Bailey hasn’t captained Australia since the early stages of the 2015 World Cup, but he looked every bit the mature player as he helped chase down the target with four overs to spare.
While other touring batsman have struggled on the turning wickets, the typically conventional Bailey reinvigorated his game with a number of reverse sweeps.
“You just need options here,” he said.
“There’s no doubt there’s some clever bowlers in that team and you just need to mix things up and change the field a little bit when you need to.”
There were also contributions from Aaron Finch (30 off 29 deliveries), Travis Head (36 off 48) and Matthew Wade (42 off 55), before quick wickets ensured some late jitters.
The match was sealed when Adam Zampa struck the winning runs on a Tillakaratne Dilshan dropped catch.
Earlier, Dinesh Chandimal was the backbone of the Sri Lanka innings, contributing a smart 102 before being the last man out.
Veteran opener Dilshan also looked dangerous before falling for 42 on his ODI farewell.
For the third successive match Australian fast-bowler Mitchell Starc (2-42) took a wicket in the first over of the match, this time dismissing Danushka Gunathilaka for 5.
But it was leg-spinner Zampa who impressed the most, with his 3-38 helping put the brakes on Sri Lanka, who at one stage were 2-96 and scoring at five an over.
Australia will have the opportunity to wrap up the ODI series, and partly atone for a 3-0 Test series defeat, when the fourth match is played in Dambulla on Wednesday.
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