An aggressive 71-run stand from Josh Inglis and Glenn Maxwell powered Australia to a six-wicket win and their fourth straight Twenty20 victory over Sri Lanka at the Melbourne Cricket Ground on Friday.
Chasing 139 for eight, the home team reached the mark for the loss of four wickets with 11 balls to spare.
Inglis smacked 40 off 20 balls while Maxwell stroked a composed 48 off 39.
"Josh has been so impressive, he's got so many options around the ground, he's so hard to bowl to," said skipper Aaron Finch, who also paid tribute to Maxwell.
"Because Inglis got off to such a flyer, he (Maxwell) was able to just sit back and play second fiddle, which he doesn't do very often. To see him play a mature role and get us over the line was humbling."
With the home side having an unassailable lead in the five-match series, they rested bowling kingpins Josh Hazlewood, Pat Cummins and Mitchell Starc.
It left Jhye Richardson, Daniel Sams and Kane Richardson to shoulder the pace load.
Opener Pathum Nissanka made 46 for Sri Lanka, but tidy bowling from spinners Ashton Agar and Adam Zampa blunted their charge, and a late collapse saw six wickets fall for 12 runs in 21 deliveries.
"There are a few positives, but again, not enough runs on the board," said Sri Lanka captain Dusan Shanaka. "Hopefully we'll come back better in the next game and pull out a win."
Australia elevated Agar to open with Ben McDermott in the run chase.
But McDermott was comfortable and was caught and bowled by Maheesh Theekshana for nine as Australia crawled to 22 for one from the first five overs.
Usual opener Finch came in at three, and with Agar struggling to get the scoreboard moving, went for a big hit off Lahiru Kumara and was caught near the boundary for two.
Attempting to up the pace, Agar began swinging the bat and he also fell to Kumara for 26 as Australia reached 64 for three at the halfway mark, needing 76 off the last 10 overs.
Maxwell and Inglis ensured they got there, whacking 23 off two overs mid-match early in their partnership, and they kept the momentum going.
Inglis finally fell to Dushmantha Chamerra, leaving Maxwell and Marcus Stoinis (8) to finish it off.
Earlier, Nissanka and Danushka Gunathilaka whacked 35 from the first four overs in Sri Lanka's best start of the series, with improved running between the wicket.
But the inconsistent Gunathilaka didn't last, out for 17 going for a slog when Agar was brought on.
Nissanka steered them to 73 for one after 10 overs alongside Kusal Mendis, who hit two big sixes as he raced to 27, before falling victim to a superb run-out by Maxwell.
But the runs dried up as the spinners took control.
Charith Asalanka (22) fell to Jhye Richardson and was followed three runs later by Nissanka, stumped by Matthew Wade off Zampa, sparking the collapse.
Dinesh Chandimal (2), Shanaka (1), Chameera (1) and Theekshana (3) all quickly followed before they plundered 17 runs from the last over to set a decent target.
Australia v Sri Lanka 4th T20 scoreboard
P. Nissanka st Wade b Zampa 46
D. Gunathilaka c Finch b Agar 17
K. Mendis run out 27
C. Asalanka c Inglis b J. Richardson 22
D. Chandimal c Finch b K. Richardson 2
D. Shanaka c Agar b K. Richardson 1
C. Karunaratne not out 14
D. Chameera b J. Richardson 1
M. Theekshana run out 3
J. Vandersay not out 5
Extras (w1) 1
Total (8 wkts; 20 overs) 139
Fall of wickets: 1-35 (Gunathilaka), 2-76 (Mendis), 3-110 (Asalanka), 4-113 (Nissanka), 5-116 (Chandimal), 6-117 (Shanaka), 7-119 (Chameera), 8-122 (Theekshana)
Bowling: Sams 2-0-14-0, J. Richardson 4-0-20-2, K. Richardson 4-0-44-2, Maxwell 2-0-21-0, Agar 4-0-14-1, Zampa 4-0-26-1
Did not bat: Lahiru Kumara
B. McDermott c&b Theekshana 9
A. Agar c Mendis b Kumara 26
A. Finch c Gunanthilaka b Kumara 2
G. Maxwell not out 48
J. Inglis c Chandimal b Chameera 40
M. Stoinis not out 8
Extras (lb3, w7) 10
Total (4 wkts; 18.1 overs) 143
Fall of wickets: 1-19 (McDermott) 2-32 (Finch), 3-49 (Agar), 4-120 (Inglis)
Bowling: Theekshana 4-0-20-1, Kumara 4-0-22-1, Karunaratne 2.1-0-22-0, Chameera 4-0-33-1, Vandersay 4-0-43-0
Did not bat: Matthew Wade, Daniel Sams, Jhye Richardson, Kane Richardson, Adam Zampa
Toss: Australia