Australia 117 for 4 in 25.4 overs (Warner 55*, Narine 2-36) beat West Indies 116 in 32.3 overs (Zampa 3-16, Lyon 3-39) by six wickets
Scorecard and ball-by-ball details
"Spin to win" became Australia's new catchphrase as Nathan Lyon and Adam Zampa left West Indies nursing a six-wicket loss. Mitchell Starc, on his return from foot surgery, added considerable venom to the cause even if his control was still some way short of his 2015 best.
Much had been made of Starc's recall, but it was the spin of Lyon, Zampa and Glenn Maxwell that mired the hosts on another sluggish pitch at Providence Stadium in Guyana. From 50 for 1, West Indies were rounded up for 116 in 32.3 overs. Though Sunil Narine and Sulieman Benn were also able to extract considerable turn, it was nowhere near enough to defend against David Warner in his post-IPL afterglow.
Not included in Australia's World T20 campaign in India earlier in the year, Lyon bowled beautifully and might easily have had more than three wickets. The umpires set a high bar for lbw decisions off deliveries straightening down the line of the stumps from around the wicket.
Umpiring vagaries aside, Lyon was aided by a canny spell from Zampa and an effective two-over cameo from Maxwell. Their variations made life difficult for a West Indies batting line-up lacking composure - the three spinners contributed combined figures of 17.3-3-58-7. Zampa's stint included artful use of line and pace to defeat the West Indies captain Jason Holder.
After the toss was delayed by 10 minutes due to damp patches in the outfield following earlier rain, Australia captain Steven Smith chose to bowl, expecting early swing and later some spin on the slow and tacky surface.
He was vindicated in the first over when Andre Fletcher narrowly avoided falling lbw due to an inside edge when Starc swerved the ball back in late. Fletcher didn't survive past that first over, slicing a fast one angled across him into the safe hands of Maxwell at backward point.
Darren Bravo and Johnson Charles prospered briefly and took West Indies to 50 for 1, but Lyon had already begun to cause some awkward moments. The pressure told at the other end as Mitchell Marsh coaxed Bravo to push a catch into the juggling hands of Zampa at extra cover.
Smith followed up the wicket by bringing Starc back, a decision rewarded by a screeching yorker that plucked Charles' leg stump off an inside edge. Starc's radar was occasionally astray, particularly in delivering numerous full tosses, but his speeds were seldom much slower than 150kph.
From there the middle order was flummoxed by Lyon, Maxwell and Zampa, as the bowling, the pitch and some hare-brained batting all contributed.
Marlon Samuels was unable to cover an off break that would have struck leg stump. Kieron Pollard was beaten in flight the next ball and pouched by an exultant Warner at long-on. And when Denesh Ramdin was not far enough down the wicket to ward off an lbw verdict in Maxwell's favour, West Indies had slumped to 85 for 6.
Zampa allowed Holder and Brathwaite to cut him on a few occasions, before completing a fine piece of deception as a faster, flatter delivery held down the seam skidded under Holder's bat and tilted the off stump.
The bespectacled Benn offered Lyon the tamest of return catches, leaving Carlos Brathwaite to try to salvage some sort of total for his side before he too was deceived by Zampa.
This all felt a long way from Brathwaite's moment of glory at Eden Gardens a few short months ago, and even with the wiles of Narine in harness, West Indies had only the faintest hope of staving off a successful Australian chase.
Warner maintained the superlative batting touch that led Sunrisers Hyderabad to the IPL title. He was busy at the crease, pushing when running between the wickets and showing good judgment of when and how to attack on a pitch that gave him little pace to work with.
Aaron Finch was less certain, and ultimately fell lbw when trying to flick Holder off the stumps. Usman Khawaja's cameo was attractive until he got an ugly front edge off Benn. An offspinner from Narine - sliding down leg in the replay - had Smith lbw. Maxwell played loosely at a sharp offbreak from Narine, leaving Marsh to help Warner cobble the final few runs as the floodlights took effect.
Nevertheless, it was a commanding victory, with six wickets and 24.2 overs to spare, which meant Australia claimed a bonus point as well. It was hard to see Lyon and Zampa being dislodged from the XI for the remainder of the tournament, let alone Tuesday's match against South Africa.
Daniel Brettig is an assistant editor at ESPNcricinfo. @danbrettig