Bravo went on to make an unbeaten 47 on Saturday as the West Indies made 196-4, plundering 123 runs from their last 10 overs against a limp Australian attack.
Australia matched the West Indies' tempo at first as Mitchell Marsh made a second consecutive half century, following his 51 in the first match of the series with 54 from 42. But for the second time the rest of
Australia's batsmen provided little resistance and the tourists were bowled out for 140 with four balls remaining.
For the second time in the series, Australia captain Aaron Finch's decision to bowl on winning the toss seemed unfounded. His leading bowlers again struggled in West Indies conditions with Mitchell Starc conceding 49 runs from his four overs after returning 0-40 in the first match.
Lendl Simmons provided solidity at the top of the order for the West Indies with 30 from 21 balls before Hetmyer stepped up to play the vital anchor role through the middle of the innings.
Hetmyer reached his second T20 international 50 from 29 balls, going to the milestone with a six off Starc. He finished with four sixes and two fours, taking his 61 runs from 36 balls before being run out in the 18th over.
"I think it was one of my best T20 innings," Hetmyer said.
"I think I paced it quite well. It really worked out for me with the guys backing me and giving me that role to be the person to take it as deep as possible. Once you do, you have a free license really and kudos to the team for giving me that role."
There wasn't much between the West Indies and Australia in the first half of each innings. The West Indies were 46-2 after the power play where Australia was 42-2 and both teams were 59-3 at the end of eight overs.
But the West Indies innings flourished in its second half where Australia's wilted, not as spectacularly as in the first match when it lost 6-19 to lose by 18 runs.
The West Indies backed up their batting performance with another outstanding effort in the field.
Sheldon Cottrell came into the match for Obed McCoy, rested for workload reasons, and bowled superbly at the top of the innings, taking 2-22.
Hayden Walsh junior bowled an excellent spell of leg spin through the middle of the innings, troubling the Australian batsmen with his pace-off style and finishing with 3-29. Chris Gayle bowled Josh Hazlewood with his second delivery in the final over to end the Australian innings.
"Chasing 190 you have to get off to a pretty good start and when your two openers get out cheaply it puts a lot of pressure on a reasonably inexperienced middle order," Finch said.
A 103 run partnership between Hetmyer and Bravo, that was the difference between the teams.
"If you can get that, you start to put pressure back onto the opposition and we just didn't have a chance to do that."