Glenn Maxwell has clubbed the fastest Twenty20 international century on Australian soil to propel his country to a series win against the West Indies.

Maxwell blasted an unbeaten 120 from 55 balls in a Sunday night feast on West Indies' bowlers at Adelaide Oval.

His masterly knock, featuring eight sixes and 12 fours, propelled Australia to 4-241 and the West Indies managed 9-207 in reply.

The 34-run victory gives Australia an unassailable 2-0 lead in the best-of-three series.

Maxwell reached his century from just 50 balls - two balls quicker than the previous fastest in a T20I in Australia, South African Rilee Rossouw's 52-ball ton against Bangladesh in Sydney at the 2022 World Cup.

Maxwell, Aaron Finch and Josh Inglis share the Australian record for fastest T20I centuries - 47 balls, all in overseas fixtures.

The 35-year-old Maxwell also equalled Indian great Rohit Sharma with the most T20I centuries - five.

The Victorian's innings was a classic counter-punch, reviving Australia from a wobbly 3-64 in the seventh over.

"I was really focused," Maxwell said.

"I was pretty calm and just really clear, it felt like it, the whole way through the innings.

"I made a few mistakes early in the innings when I got balls I felt like I could hit for boundaries and didn't quite place, probably tried to over-play the ball.

"And once I hit the gaps and hit a couple out of the middle, I was able to manipulate the field as much as I possibly could.

"I just gave myself a really good platform, which is the recipe I have been trying to give myself as much as I possibly can at international level."

Maxwell, batting at No.4, dominated an Australian innings also featuring cameos from Tim David (31no from 14 balls), captain Mitchell Marsh (29 from 12) and David Warner (22 from 19).

Maxwell reached his half-century from 25 balls and kept that pace to his ton, blending audacious shot-making with pure strokeplay.

He twice cleared the fence with switch-hits and also smacked a six over wide long-on measured by ball tracking to travel 109 metres.

"I just thought ... to make sure I cashed in and batted for as long as I possibly could," he said.

"In my brain, I have got easy boundaries where I feel like I've moved the bowler into a position where I know where they're going to bowl and I've got a gap in mind that I want to hit it there.

"And anything else, I just try and react and adapt to."

Australia's total was the nation's fourth-highest in a T20I.

The benchmark is 3-263 against Sri Lanka in Pallekele in 2016 when Maxwell made his career-best 145 not out.

The West Indies, in their run chase, were never in the hunt after losing five wickets inside their initial seven overs.

Captain Rovman Powell (63 from 36 balls) top-scored and Andre Russell (37 from 16) chipped in, while Australian allrounder Marcus Stoinis claimed 3-36.

Left-arm quick Spencer Johnson (2-39) replaced Sean Abbott who has also been ruled out of Tuesday's series finale because of a shoulder injury.