Opener David Warner struck form with an attacking 65 to help Australia to their second successive victory in the Twenty20 World Cup with a seven-wicket thrashing of Sri Lanka on Thursday.

Warner, who was dropped from his IPL team Sunrisers Hyderabad last month after two bad games, smashed 10 fours in his 42-ball knock as Australia achieved their target of 155 with 18 balls to spare in Dubai. 

Warner and skipper Aaron Finch, who made 37, took apart the Sri Lankan bowlers with an opening stand of 70.

Leg-spinner Adam Zampa returned impressive figures of 2-12 to help restrict Sri Lanka to 154-6 despite Bhanuka Rajapaksa's unbeaten 33 off 26 balls.

In reply the left-right batting pair of Warner and Finch punished the opposition pace bowlers with regular boundaries while successfully thwarting mystery spinner Maheesh Theekshana.

Leg-spinner Wanindu Hasaranga got Finch against the run of play as the batsman chopped a googly onto his stumps. He hit 37 off 23 deliveries.

Glenn Maxwell's promotion to number three did not bear results as he fell in Hasaranga's next over for five, but there was no stopping Warner.

The left-handed batsman, who survived a reprieve on 18 when wicketkeeper Kusal Perera dropped an easy catch off Dushmantha Chameera, reached his fifty in 31 balls.

Warner finally fell to Dasun Shanaka before Steve Smith, who made 28, and Marcus Stoinis, who made 16, carried the team home.

Earlier Zampa checked Sri Lanka's brisk start after Charith Asalanka and Kusal Perera - both scoring 35 - put on 63 for the second wicket.

Pat Cummins struck first with the wicket of Pathum Nissanka in the third over of the innings, but new man Asalanka soon hit bat back with three straight boundaries off the fast bowler.

The left-handed Asalanka kept up the charge and took on Maxwell's spin as Sri Lanka managed 64 runs off the first six overs of powerplay.

Zampa broke through with his leg spin googly to get Asalanka caught at backward square leg.

Mitchell Starc bowled Perera, a left-handed wicketkeeper-batsman, with a scorching yorker in the next over with Australia making inroads into the opposition middle order.

Zampa took down Avishka Fernando and Starc sent back Wanindu Hasaranga for four as Sri Lanka slipped to 94-5 in the 13th over.

Rajapaksa stood firm to see off Zampa's fourth over before launching an attack as he smashed Marcus Stoinis for two fours and a six in a 17-run over.

The left-handed Rajapaksa and Shanaka put together 40 runs off 32 balls before the captain walked back for 12 off Cummins.

Rajapaksa hit four fours and one six in his 26-ball knock but the innings wasn't enough for Sri Lanka, who went down to their first loss in the second stage. 

They had beaten Bangladesh in their opener. 

Australia v Sri Lanka T20 World Cup scoreboard

Sri Lanka

P. Nissanka c Warner b Cummins            7

K. Perera b Starc                        35

C. Asalanka c Smith b Zampa              35

A. Fernando c Smith b Zampa               4

B. Rajapaksa not out                     33

W. Hasaranga c Wade b Starc               4

D. Shanaka c †Wade b Cummins             12

C. Karunaratne not out                    9

Extras (lb4, nb1, w10)                   15

Total (6 wickets, 20 overs)             154

Did not bat: D. Chameera, L. Kumara, M. Theekshana

Fall of wickets: 1-15 (Nissanka), 2-78 (Asalanka), 3-86 (Perera), 4-90 (Fernando), 5-94 (Hasaranga), 6-134 (Shanaka)

Bowling: Starc 4-0-27-2, Hazlewood 4-0-26-0, Cummins 4-0-34-2, Maxwell 1-0-16-0, Stoinis 3-0-35-0, Zampa 4-0-12-2

Australia (target 155)

D. Warner c Rajapaksa b Shanaka          65

A. Finch b Hasaranga                     37

G. Maxwell c Fernando b de Silva          5

S. Smith not out                         28

M. Stoinis not out                       16

Extras (nb2, w2)                          4

Total (3 wickets 17 overs)              155

Did not bat: M. Marsh, M. Wade, P. Cummins, M. Starc, A. Zampa, J. Hazlewood 

Fall of wickets: 1-70 (Finch), 2-80 (Maxwell), 3-130 (Warner)

Bowling: Karunaratne 2-0-19-0 (w1), Theekshana 4-0-27-0, Chameera 3-0-33-0 (nb1), Kumara 3-0-48-0, Hasaranga 4-0-22-2 (nb1), Shanaka 1-0-6-1 (w1)

Toss: Australia

Result: Australia won by seven wickets