Former captain Smith joined Warner at the crease after the third ball of the innings and the pair's unbeaten 117-run stand mowed down Sri Lanka's total of 117 in 13 overs under the lights at the Gabba.

The win gave Aaron Finch's team an unassailable 2-0 lead in the three-match series, having thrashed the south Asians by 134 runs in Sunday's opener at Adelaide Oval.

Warner, who scored an unbeaten 100 to be man-of-the-match in Adelaide on his 33rd birthday, was 60 not out from 41 balls, with Smith finishing unbeaten on 53.

Dominant performances back-to-back from Australia's bowlers ensured the series win, with the pacemen snaring four wickets to match the spinners as Sri Lanka's batsmen struggled with the pace and bounce of the Gabba pitch.

Smith was denied a bat in Adelaide due to Warner and Finch's dominant opening stand but there was no rust at the Gabba as he savoured his first T20 knock in three-and-a-half years.

"Yeah, we played well tonight, I thought the bowlers did a terrific job early on," said Smith.

"It's good to be back now, obviously (there is) a T20 World Cup next year that I'd love to be a part of. It was nice to contribute with a few runs tonight."

Australia rested regular left-arm paceman Mitchell Starc and his towering replacement Billy Stanlake grabbed two wickets, including bowling Danushka Gunathilaka for 21 after the opener threatened to get Sri Lanka off to a solid start.

Fellow quick Pat Cummins, and spinners Ashton Agar and Adam Zampa grabbed two wickets apiece.

Sri Lanka got lucky to dismiss Finch for a duck with a leg-side catch but their bowlers had no answers for Smith and Warner.

Lasith Malinga's team now have little time to work things out before they head to Melbourne for the final dead rubber on Friday.

"We didn't expect that score, we were expecting 150," said Malinga, who pinned the loss squarely on his batsmen.

"I think for this game, the positives were only the preparation for the T20 World Cup in these conditions."