Sri Lanka assistant coach Rumesh Ratnayake was "gutted" after another poor batting performance proved costly against Australia in a Twenty20 international.

Chasing 234 to win the series opener in Adelaide, Sri Lanka were restricted to 99-9 last Sunday.

And another one-sided contest played out in Brisbane on Wednesday, as the tourists were bowled out for 117 with one over to spare.

Just two Sri Lanka batsmen passed 20 as quicks Billy Stanlake and Pat Cummins and spinners Ashton Agar and Adam Zampa took two wickets each.

Australia then chased down a victory target of 118 in 13 overs, with David Warner (60 not out) and Steve Smith (53 not out) guiding their side to a convincing nine-wicket win.

"Disappointed is ... I think it's too nice a word," Ratnayake told reporters, with Australia now holding an unbeatable 2-0 series lead with one to play.

"I'm gutted, really. The boys are gutted. But [it is] unacceptable because the way we batted ... [it was] as if we, at times, we thought we were going to be all out in the 12th over or so.

"We are going to rectify it. We are going to sort of revisit [it] in our meetings and see what went wrong. It is intent which I feel was not there."

Sri Lanka entered the three-match series in Australia fresh off a 3-0 whitewash of world number one side Pakistan.

Making that triumph even better was the fact it came in Pakistan, but Sri Lanka have struggled on the fast, bouncy Australian pitches.

Ratnayake said it was a priority to correct that ahead of next year's T20 World Cup, to be played in Australia from October to November.

"Our preparation needs to be much more ... it needs to have at least a period of six weeks," he said.

"We came directly - virtually directly from Pakistan. The sub-continent wickets are different from these ... no excuses though.

"Adaptation was the thing which we did not do in the past two matches."

Australia paceman Stanlake was pleased with his night's work but preferred to talk up former Test captain Smith, who caught the eye with a terrific half-century.

"It's exciting for us. I think it's exciting for the public as well, just to watch him play T20 cricket," Stanlake said.

"Obviously, they don't get to see him do that too much.

"But yeah, he is an absolute class player, you saw how he good was tonight, again. He does it in all formats and hopefully we can see him doing it often."

The three-match Twenty20 international series concludes in Melbourne on Friday.